[PDF]    http://dx.doi.org/10.3952/lithjphys.44102

Open access article / Atviros prieigos straipsnis

Lith. J. Phys. 44, 17–26 (2004)


PHOTOEXCITATION OF POLARIZED ATOMS BY POLARIZED RADIATION
A. Kupliauskienė
Vilnius University Research Institute of Theoretical Physics and Astronomy, A. Goštauto 12, LT-01108 Vilnius, Lithuania
E-mail: akupl@itpa.lt

Received 1 December 2003

An expression for the probability of the excitation of polarized atoms by polarized radiation is obtained by using the graphical technique of angular momentum. In the case of pure states, the applied method is an alternative to that of density matrix formalism. The obtained expression enables one to describe the polarization state of an excited atom and can be used to derive formulas for the special cases under specific experimental conditions as well as for the photoexcitation as the first step process. The application of obtained expressions for the description of multistep processes is discussed. The photoexcitation of unpolarized atoms by polarized radiation and polarized atoms by unpolarized radiation is considered as the examples of practical application of the obtained general expression.
Keywords: excited atoms, polarization, photoexcitation
PACS: 31.50.Df, 29.25.Pj


POLIARIZUOTO ATOMO SUŽADINIMAS POLIARIZUOTA SPINDULIUOTE
A. Kupliauskienė
VU Teorinės fizikos ir astronomijos institutas, Vilnius, Lietuva

Derinamo dažnio lazerio ir sinchrotroninė spinduliuotės atveria galimybę ne tiktai jonizuoti atomus, atplėšiant elektronus iš pageidaujamo sluoksnio, bet ir juos sužadinti į pageidaujamą būseną. Šitaip paruošiami poliarizuoti atomai, kurie toliau naudojami poliarizacijos reiškiniams jonizuojant atomus elektronais ir fotonais tirti. Norint vieningai teoriškai aprašyti atomo sužadinimo ir po jo einančius jonizacijos vyksmus bei tirti, kaip antrąjį vyksmą apibūdinantys dydžiai priklauso nuo pirmojo, reikalingos kuo bendresnės tokius vyksmus aprašančios formulės. Panaudojant judėjimo kiekio momento grafinį vaizdavimą ir atomo teorijos metodus, surasta poliarizuoto atomo sužadinimo poliarizuota spinduliuote tikimybės išraiška. Grynųjų būsenų atveju panaudotasis metodas yra alternatyvus iki šiol taikytam tankio matricos formalizmui. Surastoji formulė taip pat aprašo sužadinto atomo poliarizaciją. Ji panaudota nepoliarizuoto atomo sužadinimo poliarizuota spinduliuote ir poliarizuoto atomo sužadinimo nepoliarizuota spinduliuote tikimybės išraiškoms rasti, laikant, kad sužadinimas tėra pirmoji tolimesnio vyksmo stadija. Taip pat parodyta, kokius pakeitimus reikia padaryti, kad formulės būtų pritaikytos daugiapakopiams vyksmams aprašyti.


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