Gotowa bibliografia na temat „Elastic Sherman function”

The differential, total, and momentum transfer cross sections along with the minima in the differential cross sections (DCSs) and the Sherman function S(θ) for the elastic scattering of electrons by calcium atoms have been calculated. These calculations are done within the framework of complex electron–atom optical potential and relativistic dynamics, in the energy range 1–2000 eV. The results obtained are in good agreement with the available experimental data and are better than the previous calculations in overall assessment. In the DCSs, the energies and angular positions of five critical minima have been confirmed. In the vicinity of these critical minima, nine maximum polarization points have been found within the range −0.90 ≤ S(θ) ≤ +0.73. Near the critical minima, a strong energy dependence of maximum polarization points is found.

Theoretical investigation of the scattering of electrons and positrons from the plasma etching gas trifluoroiodomethane (CF3I) is presented in the present work. The investigation is carried out by taking into account the screening correction arising from a semiclassical analysis of atomic geometrical overlapping of the scattering cross-sections calculated in the independent atom approximation. The scattering system e±-CF3I is studied through the calculations of the observable quantities, namely, absolute differential, Sherman function, total elastic and inelastic, momentum transfer, viscosity, ionization and total cross sections over the energy range 1 eV–1 MeV. Energy dependency of the differential cross section and Sherman function are also picturized in this work. A comparative study is carried out between scattering observables for electron impact with those for positron impact to get a better understanding of the interaction and dynamics of the collision process. The corresponding scattering quantities of the constituent atoms are calculated employing a complex optical model potential by solving the Dirac relativistic wave equations in the framework of partial wave analysis. The comparison of our results with the available experimental and theoretical data shows a reasonable agreement.

The present work reports the theoretical investigation of the scattering of electrons and positrons by the ethane (C2H6) molecule over the energy range 1 eV–1 MeV. The investigation was carried out by taking into account the screening correction arising from a semiclassical analysis of the atomic geometrical overlapping of the scattering observables calculated in the independent atom approximation. The study is presented through the calculations of a broad spectrum of observable quantities, namely differential, integrated elastic, momentum transfer, viscosity, inelastic, grand total, and total ionization cross-sections and the Sherman functions. A comparative study was carried out between scattering observables for electron impact with those for positron impact to exhibit the similarity and dissimilarity arising out of the difference of the collisions of impinging projectiles with the target. Partial-wave decomposition of the scattering states within the Dirac relativistic framework employing a free-atom complex optical model potential was used to calculate the corresponding observable quantities of the constituent atoms. The results, calculated using our recipe, were compared with the experimental and theoretical works available in the literature. The Sherman function for a e±−C2H6 scattering system is presented for the first time in the literature. The addition of the screening correction to the independent atom approximation method was found to substantially reduce the scattering cross-sections, particularly at forward angles for lower incident energies.

Calculations are presented for differential, integrated elastic, momentum transfer, viscosity, inelastic, total cross sections and spin polarization parameters S, T and U for electrons and positrons scattering from atoms and ions of radon isonuclear series in the energy range from 1 eV–1 MeV. In addition, we analyze systematically the details of the critical minima in the elastic differential cross sections along with the positions of the corresponding maximum polarization points in the Sherman function for the aforesaid scattering systems. Coulomb glory is investigated across the ionic series. A short range complex optical potential, comprising static, polarization and exchange (for electron projectile) potentials, is used to describe the scattering from neutral atom. This potential is supplemented by the Coulomb potential for the same purpose for a charged atom. The Dirac partial wave analysis, employing the aforesaid potential, is carried out to calculate the aforesaid scattering observables. A comparison of our results with other theoretical findings shows a reasonable agreement over the studied energy range.

This article reports on the scattering of unpolarized and spin polarized electrons and positrons from 28Ni58,29Cu63,46Pd108, and 78Pt196, covering light to heavy precious metal targets. To cover the wide energy domain of 1 eV ≤Ei≤300 MeV, Dirac partial-wave phase-shift analysis is employed, using a complex optical potential for Ei≤1 MeV and a potential derived from the nuclear charge distribution for Ei>1 MeV. Results are presented for the differential and integral cross-sections, including elastic, momentum transfer, and viscosity cross-sections. In addition, the inelastic, ionization, and total (elastic + inelastic) cross-section results are provided, together with mean free path estimates. Moreover, the polarization correlations S,T, and U, which are sensitive to phase-dependent interference effects, are considered. Scaling laws with respect to collision energy, scattering angle, and nuclear charge number at ultrahigh energies are derived using the equivalence between elastic scattering and tip bremsstrahlung emission. In addition, a systematic analysis of the critical minima in the differential cross-section and the corresponding total polarization points in the Sherman function S is carried out. A comparison with existing experimental data and other theoretical findings is made in order to test the merit of the present approach in explaining details of the measurements.

This article incorporates details of our calculations of the observable quantities for the scattering of electrons and positrons from a post transition metal Thallium (Tl), in the energy range of 1 eV ≤ Ei ≤ 1 MeV, using the relativistic Dirac partial wave (phase-shift) analysis employing a complex optical-potential. Absolute differential, integrated elastic and inelastic, transport, total ionization, and total cross sections and a thorough study of the critical minima in the elastic differential cross sections along with the associated angular positions of the maximum polarization points in the Sherman function are provided to study the collision dynamics. The optical potential model incorporates the interactions of the incident electron and/or positron with both the nucleus and the bound electrons of the target atom. In-depth analyses of the spin asymmetry, which are sensitive to phases related interference effect, brought on by the various ingredients of the lepton-atom interaction, are also presented. The performance of the current approach to explain the observations, with the exception of the extremely low energy domain, is shown by a comparison of the previous experimental and theoretical results on this target atom.

Abstract The current study investigates the scattering of electron and positron from aluminum isonuclear series within the framework of the Dirac relativistic partial wave analysis. For the neutral aluminum atoms the scattering phenomena are described by employing a short range complex optical potential. For the ionic series, on the other hand, this potential is supplemented by the Coulomb potential. The calculations are reported for the differential cross section, total cross section, integrated elastic cross section, inelastic cross section, momentum transfer cross section, viscosity cross section and total ionization cross section over the energy range 1 eV ≤ Ei ≤ 1 MeV. The Sherman function S and spin asymmetry parameters T and U are also predicted for the same scattering systems over the same energy range. In addition, for the first time, we report a systematic study of the critical minima in the differential cross sections as well as the associated maximum spin polarization points in the Sherman function. We also compute the inelastic, elastic, momentum transfer, viscosity and total mean free paths for the aforesaid scattering systems. The Coulomb glory effect, the amplifi cation of elastic back scattering of electrons from positive ions, is examined throughout the ionic series of aluminum. A comparison of our results to the reported theoretical and experimental studies reveals a good consistency over the compared energy range. The present theoretical method is thus expected to be useful for the fast generation of accurate cross sections needed in many areas of science, technologies and industries.

Introduction It used to be the case that for the mass of workers, work was something that was done in order to get by. A working class was simply the sum total of all those workers and their dependents whose wages paid for the necessities of life, providing the bare minimum for family reproduction, to secure a place and a lineage within the social order. However, work has now become something else. Work has become the privileged sign of a new kind of class, whose existence is guaranteed not so much by work, but by the very fact of holding a job. Society no longer divides itself between a ruling elite and a subordinated working class, but between a job-holding, job-aspiring class, and those excluded from holding a job; those unable, by virtue of age, infirmity, education, gender, race or demographics, to participate in the rewards of work. Today, these rewards are not only a regular salary and job satisfaction (the traditional consolations of the working class), but also a certain capacity to plan ahead, to gain control of one's destiny through saving and investment, and to enjoy the pleasures of consumption through the fulfilment of self-images. What has happened to transform the worker from a subsistence labourer to an affluent consumer? In what way has the old working class now become part of the consumer society, once the privileged domain of the rich? And what effects has this transformation had on capitalism and its desire for profit? These questions take on an immediacy when we consider that, in the recent Federal election held in Australia (November 11, 2001), voters in the traditional working class areas of western Sydney deserted the Labour Party (the party of the worker) and instead voted Liberal/conservative (the party of capital and small business). The fibro worker cottage valleys of Parramatta are apparently no more, replaced by the gentrified mansions of an aspiring worker formation, in pursuit of the wealth and independence once the privilege of the educated bourgeoisie. In this brief essay, I will outline an understanding of work in terms of its changing relation to capital. My aim is to show how the terrain of work has shifted so that it no longer operates in strict subordination to capital, and has instead become an investment in capital. The worker no longer works to subsist, but does so as an investment in the future. My argument is situated in the rich theoretical field set out by Karl Marx in his critique of capitalism, which described the labour/capital relation in terms of a repressive, extractive force (the power of capital over labour) and which has since been redefined by various poststructuralist theorists including Michel Foucault and Gilles Deleuze (Anti-Oedipus) in terms of the forces of productive desire. What follows then, is not a Marxist reading of work, but a reading of the way Marx sets forth work in relation to capital, and how this can be re-read through poststructuralism, in terms of the transformation of work from subordination to capital, to investment in capital; from work as the consequence of repression, to work as the fulfilment of desire. The Discipline of Work In his major work Capital Marx sets out a theory of labour in which the task of the worker is to produce surplus value: "Capitalist production is not merely the production of commodities, it is, by its very essence, the production of surplus-value. The worker produces not for himself, but for capital. It is no longer sufficient, therefore, for him simply to produce. He must produce surplus-value." (644) For Marx, surplus-value is generated when commodities are sold in the market for a price greater than the price paid to the worker for producing it: "this increment or excess over the original value I call surplus-value" (251). In order to create surplus value, the time spent by the worker in making a commodity must be strictly controlled, so that the worker produces more than required to fulfil his subsistence needs: ". . . since it is just this excess labour that supplies [the capitalist] with the surplus value" (1011). In other words, capital production is created through a separation between labour and capital: "a division between the product of labour and labour itself, between the objective conditions of labour and the subjective labour-power, was . . . the real foundation and the starting point of the process of capital production" (716). As Michael Ryan has argued, this separation was forced , through an allegiance between capital and the state, to guarantee the conditions for capital renewal by controlling the payment of labour in the form of a wage (84). Marx's analysis of industrialised capital in Capital thus outlines the way in which human labour is transformed into a form of surplus value, by the forced extraction of labour time: "the capitalist forces the worker where possible to exceed the normal rate of intensity [of work] and he forces him as best he can to extend the process of labour beyond the time necessary to replace the amount laid out in wages" (987). For Marx, capitalism is not a voluntary system; workers are not free to enter into and out of their relation with capital, since capital itself cannot survive without the constant supply of labour from which to extract surplus value. Needs and wants can only be satisfied within the labour/capital relation which homogenises labour into exchange value in terms of a wage, pegged to subsistence levels: "the capital earmarked for wages . . . belongs to the worker as soon as it has assumed its true shape of the means of subsistence destined to be consumed by him" (984). The "true shape" of wages, and hence the single, univocal truth of the wage labourer, is that he is condemned to subsistence consumption, because his capacity to share in the surplus value extracted from his own labour is circumscribed by the alliance between capital and the state, where wages are fixed and controlled according to wage market regulations. Marx's account of the labour/capital relation is imposing in its description of the dilemma of labour under the power of capital. Capitalism appears as a thermodynamic system fuelled by labour power, where, in order to make the system homogeneous, to produce exchange value, resistance is reduced: "Because it is capital, the automatic mechanism is endowed, in the person of the capitalist, with consciousness and a will. As capital, therefore, it is animated by the drive to reduce to a minimum the resistance offered by man, that obstinate yet elastic natural barrier." (527) In the capitalist system resistance takes the form of a living residue within the system itself, acting as an "elastic natural barrier" to the extractive force of capital. Marx names this living residue "man". In offering resistance, that is, in being subjected to the force of capital, the figure of man persists as the incommensurable presence of a resistive force composed by a refusal to assimilate. (Lyotard 102) This ambivalent position (the place of many truths) which places man within/outside capital, is not fully recognised by Marx at this stage of his analysis. It suggests the presence of an immanent force, coming from the outside, yet already present in the figure of man (man as "offering" resistance). This force, the counter-force operating through man as the residue of labour, is necessarily active in its effects on the system. That is to say, resistance in the system is not resistance to the system, but the resistance which carries the system elsewhere, to another place, to another time. Unlike the force of capital which works on labour to preserve the system, the resistive force figured in man works its way through the system, transforming it as it goes, with the elusive power to refuse. The separation of labour and capital necessary to create the conditions for capitalism to flourish is achieved by the action of a force operating on labour. This force manifests itself in the strict surveillance of work, through supervisory practices: "the capitalist's ability to supervise and enforce discipline is vital" (Marx 986). Marx's formulation of supervision here and elsewhere, assumes a direct power relation between the supervisor and the supervised: a coercive power in the form of 'the person of the capitalist, with consciousness and a will'. Surplus value can only be extracted at the maximum rate when workers are entirely subjected to physical surveillance. As Foucault has shown, surveillance practices in the nineteenth century involved a panoptic principle as a form of surveillance: "Power has its principle not so much in a person as in a certain concerted distribution of bodies, surfaces, lights, gazes; an arrangement whose internal mechanisms produce the relation in which individuals get caught up." (202) Power is not power over, but a productive power involving the commingling of forces, in which the resistive force of the body does not oppose, but complies with an authoritative force: "there is not a single moment of life from which one cannot extract forces, providing one knows how to differentiate it and combine it with others" (165). This commingling of dominant and resistive forces is distributive and proliferating, allowing the spread of institutions across social terrains, producing both "docile" and "delinquent" bodies at the same time: "this production of delinquency and its investment by the penal apparatus ..." (285, emphasis added). Foucault allows us to think through the dilemma posed by Marx, where labour appears entirely subject to the power of capital, reducing the worker to subsistence levels of existence. Indeed, Foucault's work allows us to see the figure of man, briefly adumbrated in quote from Marx above as "that obstinate yet elastic natural barrier", but refigured as an active, investing, transformative force, operating within the capitalist system, yet sending it on its way to somewhere else. In Foucauldian terms, self-surveillance takes on a normative function during the nineteenth century, producing a set of disciplinary values around the concepts of duty and respectability (Childers 409). These values were not only imposed from above, through education and the state, but enacted and maintained by the workers themselves, through the myriad threads of social conformity operating in daily life, whereby people made themselves suitable to each other for membership of the imagined community of disciplined worker-citizens. In this case, the wellbeing of workers gravitated to self-awareness and self-improvement, seen for instance in the magazines circulating at the time addressed to a worker readership (e.g. The Penny Magazine published in Britain from 1832-1845; see Sinnema 15). Instead of the satisfaction of needs in subsistence consumption, the worker was possessed by a desire for self-improvement, taking place in his spare time which was in turn, consolidated into the ego-ideal of the bourgeois self as the perfected model of civilised, educated man. Here desire takes the form of a repression (Freud 355), where the resistive force of the worker is channelled into maintaining the separation between labour and capital, and where the worker is encouraged to become a little bourgeois himself. The desire for self-improvement by the worker did not lead to a shift into the capitalist classes, but was satisfied in coming to know one's place, in being satisfied with fulfilling one's duty and in living a respectable life; that is in being individuated with respect to the social domain. Figure 1 - "The British Beehive", George Cruickshank's image of the hierarchy of labour in Victorian England (1840, modified 1867). Each profession is assigned an individualised place in the social order. A time must come however, in the accumulation of surplus-value, in the vast accelerating machine of capitalism, when the separation between labour and capital begins to dissolve. This point is reached when the residue left by capital in extracting surplus value is sufficient for the worker to begin consuming for its own sake, to engage in "unproductive expenditure" (Bataille 117) where desire is released as an active force. At this point, workers begin to abandon the repressive disciplines of duty and respectability, and turn instead to the control mechanisms of self-transformation or the "inventing of a self as if from scratch" (Massumi 18). In advanced capitalism, where the accrued wealth has concentrated not only profit but wages as well (a rise in the "standard of living"), workers cease to behave as subordinated to the system, and through their increased spending power re-enter the system as property owners, shareholders, superannuants and debtees with the capacity to access money held in banks and other financial institutions. As investment guru Peter Drucker has pointed out, the accumulated wealth of worker-owned superannuation or "pension" funds, is the most significant driving force of global capital today (Drucker 76-8). In the superannuation fund, workers' labour is not fully expended in the production of surplus value, but re-enters the system as investment on the workers' behalf, indirectly fuelling their capacity to fulfil desires through a rapidly accelerating circulation of money. As a consequence, new consumer industries begin to emerge based on the management of investment, where money becomes a product, subject to consumer choice. The lifestyles of the old capitalist class, itself a simulacra of aristocracy which it replaced, are now reproduced by the new worker-capitalist, but in ersatz forms, proliferating as the sign of wealth and abundance (copies of palatial homes replace real palaces, look-alike Rolex watches become available at cheap prices, medium priced family sedans take on the look and feel of expensive imports, and so forth). Unable to extract the surplus value necessary to feed this new desire for money from its own workforce (which has, in effect, become the main consumer of wealth), capital moves 'offshore' in search of a new labour pool, and repeats what it did to the labour pools in the older social formations in its relentless quest to maximise surplus value. Work and Control We are now witnessing a second kind of labour taking shape out of the deformations of the disciplinary society, where surplus value is not extracted, but incorporated into the labour force itself (Mules). This takes place when the separation between labour and capital dissolves, releasing quantities of "reserve time" (the time set aside from work in order to consume), which then becomes part of the capitalising process itself. In this case workers become "investors in their own lives (conceived of as capital) concerned with obtaining a profitable behaviour through information (conceived of as a production factor) sold to them." (Alliez and Feher 347). Gilles Deleuze has identified this shift in terms of what he calls a "control society" where the individuation of workers guaranteed by the disciplinary society gives way to a cybernetic modulation of "dividuals" or cypher values regulated according to a code (180). For dividualised workers, the resource incorporated into capital is their own lived time, no longer divided between work and leisure, but entirely "consummated" in capital (Alliez and Fehrer 350). A dividualised worker will thus work in order to produce leisure, and conversely enjoy leisure as a form of work. Here we have what appears to be a complete breakdown of the separation of labour and capital instigated by the disciplinary society; a sweeping away of the grounds on which labour once stood as a mass of individuals, conscious of their rivalry with capital over the spoils of surplus value. Here we have a situation where labour itself has become a form of capital (not just a commodity exchangeable on the market), incorporated into the temporalised body of the worker, contributing to the extraction of its own surplus value. Under the disciplinary society, the body of the worker became subject to panoptic surveillance, where "time and motion" studies enabled a more efficient control of work through the application of mathematical models. In the control society there is no need for this kind of panoptic control, since the embodiment of the panoptic principle, anticipated by Foucault and responsible for the individuation of the subject in disciplinary societies, has itself become a resource for extracting surplus value. In effect, dividualised workers survey themselves, not as a form of self-discipline, but as an investment for capitalisation. Dividuals are not motivated by guilt, conscience, duty or devotion to one's self, but by a transubjective desire for the other, the figure of a self projected into the future, and realised through their own bodily becoming. Unlike individuals who watch themselves as an already constituted self in the shadow of a super-ego, dividuals watch themselves in the image of a becoming-other. We might like to think of dividuals as self-correctors operating in teams and groups (franchises) whose "in-ness" as in-dividuals, is derived not from self-reflection, but from directiveness. Directiveness is the disposition of a habitus to find its way within programs designed to maximise performance across a territory. Following Gregory Bateson, we might say that directiveness is the pathway forged between a map and its territory (Bateson 454). A billiard ball sitting on a billiard table needs to be struck in such a way to simultaneously reduce the risk of a rival scoring from it, and maximise the score available, for instance by potting it into a pocket. The actual trajectory of the ball is governed by a logic of "restraint" (399) which sets up a number of virtual pathways, all but one of which is eliminated when the map (the rules and strategies of the game) is applied to the territory of the billiard table. If surveillance was the modus operandi of the old form of capitalism which required a strict control over labour, then directiveness is the new force of capital which wants to eliminate work in the older sense of the word, and replace it with the self-managed flow of capitalising labour. Marx's labour theory of value has led us, via a detour through Foucault and Deleuze, to the edge of the labour/capital divide, where the figure of man reappears, not as a worker subject to capital, but in some kind of partnership with it. This seems to spell the end of the old form of work, which required a strict delineation between labour and capital, where workers became rivals with capital for a share in surplus value. In the new formation of work, workers are themselves little capitalists, whose labour time is produced through their own investments back into the system. Yet, the worker is also subject to the extraction of her labour time in the necessity to submit to capital through the wage relation. This creates a reflexive snarl, embedded in the worker's own self-image, where work appears as leisure and leisure appears as work, causing labour to drift over capital and vice versa, for capital to drift over labour. This drifting, mobile relation between labour and capital cannot be secured through appeals to older forms of worker awareness (duty, responsibility, attentiveness, self-surveillance) since this would require a repression of the desire for self-transformation, and hence a fatal dampening of the dynamics of the market (anathema to the spirit of capitalism). Rather it can only be directed through control mechanisms involving a kind of forced partnership between capital and labour, where both parties recognise their mutual destinies in being "thrown" into the system. In the end, work remains subsumed under capital, but not in its alienated, disciplinary state. Rather work has become a form of capital itself, one's investment in the future, and hence as valuable now as it was before. It's just a little more difficult to see how it can be protected as a 'right' of the worker, since workers are themselves investors of their own labour, and not right-bearing individuals whose position in society has been fixed by the separation of labour from capital. References Alliez, Eric and Michel Feher. "The Luster of Capital." Zone1/2 (1987): 314-359. Bataille, Georges. 'The Notion of Expenditure'. Visions of Excess: Selected Writings, 1927-1939, Trans. and Ed. Alan Stoekl. Minneapolis: Minnesota UP, 1985. 116-29. Bateson, Gregory. Steps to an Ecology of Mind. New York: Ballantine Books, 1972. Childers, Joseph W. "Observation and Representation: Mr. Chadwick Writes the Poor." Victorian Studies37.3 (1994): 405-31. Deleuze, Gilles. Anti-Oedipus: Capitalism and Schizophrenia. Minneapolis: U of Minnesota P, 1983. --. Negotiations, 1972-1990. Trans. Martin Joughin. New York: Columbia UP, 1995. Drucker, Peter F. Post-Capitalist Society. New York: Harper, 1993. Foucault, Michel. Discipline and Punish: The Birth of the Prison. Trans. Alan Sheridan. Harmondsworth: Penguin, 1977. Freud, Sigmund. "The Ego and the Id". On Metapsychology: The Theory of Psychoanalysis. The Pelican Freud Library, Vol 11. Harmondsworth: Penguin, 1984. 339-407. Lyotard, Jean-Francois. Libidinal Economy. Trans. Iain Hamilton Grant,. Bloomington: Indiana UP, 1993. Marx, Karl. Capital, Vol. I. Trans. Ben Fowkes. Harmondsworth: Penguin, 1976. Massumi, Brian. "Everywhere You Wanted to Be: Introduction to Fear." The Politics of Everyday Fear. Ed. Brian Massumi. Minneapolis: U of Minnesota P, 1993. 3-37. Mules, Warwick. "A Remarkable Disappearing Act: Immanence and the Creation of Modern Things." M/C: A Journal of Media and Culture 4.4 (2001). 15 Nov. 2001 <http://www.media-culture.org.au/0108/disappear.php>. Ryan, Michael. Marxism and Deconstruction: A Critical Introduction. Baltimore: John Hopkins Press, 1982. Sinnema, Peter W. Dynamics of the Printed Page: Representing the Nation in the Illustrated London News. Aldershot: Ashgate Press, 1998. Links http://csf.colorado.edu/psn/marx/Archive/1867-C1/ http://www.media-culture.org.au/0108/Disappear.html http://acnet.pratt.edu/~arch543p/help/Foucault.html http://acnet.pratt.edu/~arch543p/help/Deleuze.html Citation reference for this article MLA Style Mules, Warwick. "That Obstinate Yet Elastic Natural Barrier" M/C: A Journal of Media and Culture 4.5 (2001). [your date of access] < http://www.media-culture.org.au/0111/Mules.xml >. Chicago Style Mules, Warwick, "That Obstinate Yet Elastic Natural Barrier" M/C: A Journal of Media and Culture 4, no. 5 (2001), < http://www.media-culture.org.au/0111/Mules.xml > ([your date of access]). APA Style Mules, Warwick. (2001) That Obstinate Yet Elastic Natural Barrier. M/C: A Journal of Media and Culture 4(5). < http://www.media-culture.org.au/0111/Mules.xml > ([your date of access]).

This thesis presents a set of measurements of spin asymmetries from the heavy atoms krypton and rubidium. These investigations allow examination of the spin orbit interaction for electron scattering from the target atoms. These measurements utilise spin polarized electrons in a crossed beam experiment to measure the Sherman function from krypton and the A2 parameter from the 52P state of rubidium. The measurements utilise a new spin polarized electron energy spectrometer which is designed to operate in the 20-200 eV range. The apparatus consists of a standard gallium arsenide polarized electron source, a 180 degrees hemispherical electron analyser to detect scattered electrons and a Mott detector to measure electron polarization. A series of measurements of the elastic Sherman function were performed on krypton at incident electron energies of 20, 50, 60, 65, 100, 150 and 200 eV. Scattered electrons are measured over an angular range of 30-130 degrees. These measurements are compared with calculations of the Sherman function which are obtained by solution of the Dirac-Fock equations. These calculations include potentials to account for dynamic polarization and loss of flux into inelastic channels. At the energies 50, 60 and 65 eV, experimental agreement with theory is seen to be extremely dependent on the theoretical model used. Measurement of the A2 parameter from the combined 52P1/2,3/2 state of rubidium are performed at an incident energy of 20 eV. The scattered electrons are measured over an angular range of 30-110 degrees. This measurement represents the first such measurement of this parameter for rubidium. Agreement with preliminary calculations performed using the R-matrix technique are good and are expected to improve with further theoretical development.

This thesis presents a set of measurements of spin asymmetries from the heavy atoms krypton and rubidium. These investigations allow examination of the spin orbit interaction for electron scattering from the target atoms. These measurements utilise spin polarized electrons in a crossed beam experiment to measure the Sherman function from krypton and the A2 parameter from the 52P state of rubidium. The measurements utilise a new spin polarized electron energy spectrometer which is designed to operate in the 20-200 eV range. The apparatus consists of a standard gallium arsenide polarized electron source, a 180 degrees hemispherical electron analyser to detect scattered electrons and a Mott detector to measure electron polarization. A series of measurements of the elastic Sherman function were performed on krypton at incident electron energies of 20, 50, 60, 65, 100, 150 and 200 eV. Scattered electrons are measured over an angular range of 30-130 degrees. These measurements are compared with calculations of the Sherman function which are obtained by solution of the Dirac-Fock equations. These calculations include potentials to account for dynamic polarization and loss of flux into inelastic channels. At the energies 50, 60 and 65 eV, experimental agreement with theory is seen to be extremely dependent on the theoretical model used. Measurement of the A2 parameter from the combined 52P1/2,3/2 state of rubidium are performed at an incident energy of 20 eV. The scattered electrons are measured over an angular range of 30-110 degrees. This measurement represents the first such measurement of this parameter for rubidium. Agreement with preliminary calculations performed using the R-matrix technique are good and are expected to improve with further theoretical development.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Science
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