Naslov
Correlation effects in high energy photoabsorption and in Compton scattering

Autori
Surić, Tihomir

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
X05 Abstracts / - Melbourne, 2005

Skup
The 20th International Conference, X-ray and Inner-shell Processes

Mjesto i datum
Melbourne, Australija, 04.07.2005. - 08.07.2005

Vrsta sudjelovanja
Pozvano predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
Compton scattering; photoeffect; double photoionization; correlation

Sažetak
Correlation effects (the part of interaction between electrons which requires description beyond independent particle approximation (IPA) such as e.g. Hartree-Fock approximation) are generally important in describing photon--atom interaction processes, even at high energies. However, in different photon-atom processes different aspects of initial and final state correlations are important. We discuss two important type of processes occurring in photon--atom interaction: 1) photoabsorption processes (resulting in single or double ionization of atom), and 2) Compton scattering of a photon by bound electrons (also discussing processes resulting in single or double ionization of atom). Due to the fact that Compton scattering can occur also on a free electron while photoabsorption process requires the presence of another particle (nucleus or just another electron), these different processes probe different aspects of initial and final state correlations. Correlation effects important for photoabsorption processes and for Compton scattering processes are discussed using the example of Helium system (as the simplest many--electron system). We first identify correlation effects which are important for photoabsorption processes at high energies and also identify correlation effects which are important for Compton scattering processes. We then discuss the differences between the correlation effects involved in these two types of processes. In the case of photoabsorption we go beyond the leading order correlation effects [T. Suric R. H. Pratt, J. Phys B 37, L93 (2004)]. In the case of Compton scattering we propose an improvement in extracting from measurements information about complex systems. The improvement consists in generalizing the usual impulse approximation description (which serves to interpret Compton scattering measurements in terms of electron momentum density of the target) and in going beyond IPA approaches by including correlations.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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