We propose an effective procedure to fit triple differential cross sections of atomic double photoionization processes, which is based on a general expression of the transition amplitude between arbitrary states of the target atom and the parent ion, with the transition operator expressed at any order of its multipolar expansion. The major advantage of our expression, that in the dipole approximation is equivalent to those of Manakov (1996 J. Phys. B: At. Mol. Opt. Phys. 29 2711) and Malegat (1997 J. Phys. B: At. Mol. Opt. Phys. 30 251), is that it is expressed only in terms of elementary angular functions (Clebsch–Gordan coefficients, spherical harmonics and 6 − j factors). Therefore our expression can be easily implemented in a general code for any kinematic condition and any order of the multipolar expansion of the transition operator. Our fitting procedure takes into account also the finite instrumental resolution in measuring energies and angles. Test calculations on helium and argon show that this further capability is often essential to remove important discrepancies between simulated and measured angular distributions.

A general algorithm for fitting efficiently triple differential cross sections of atomic double photoionization

ARGENTI, LUCA;COLLE, RENATO
2008

Abstract

We propose an effective procedure to fit triple differential cross sections of atomic double photoionization processes, which is based on a general expression of the transition amplitude between arbitrary states of the target atom and the parent ion, with the transition operator expressed at any order of its multipolar expansion. The major advantage of our expression, that in the dipole approximation is equivalent to those of Manakov (1996 J. Phys. B: At. Mol. Opt. Phys. 29 2711) and Malegat (1997 J. Phys. B: At. Mol. Opt. Phys. 30 251), is that it is expressed only in terms of elementary angular functions (Clebsch–Gordan coefficients, spherical harmonics and 6 − j factors). Therefore our expression can be easily implemented in a general code for any kinematic condition and any order of the multipolar expansion of the transition operator. Our fitting procedure takes into account also the finite instrumental resolution in measuring energies and angles. Test calculations on helium and argon show that this further capability is often essential to remove important discrepancies between simulated and measured angular distributions.
File in questo prodotto:
Eventuali allegati, non sono esposti

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11585/65598
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 4
  • ???jsp.display-item.citation.isi??? 3
social impact