Electron induced ionization cross sections for astrophysical modelling

Abstract

This paper reports electron impact total ionization cross sections for C2 to C6 formates at energies varying from ionization threshold to 5keV. The ionization cross section data in such a wide energy range are necessary to complete data tables required for modelling different atmospheric and astrophysical environments. To compute these values, a modified approach called multi scattering centre spherical complex optical potential (MSCOP) formalism is employed. Using MSCOP, the total inelastic cross section is obtained, which corresponds to the total loss of incident flux into the dominant channels viz. discrete electronic excitation and continuum ionization. The ionization contribution from total inelastic cross section is estimated using a semi empirical complex scattering potential-ionization contribution (CSP-ic) method. The results show overall good agreement with previous measurements and theoretical estimates available from the literature. Besides cross sections, correlations between maximum ionization cross section versus the square root of the ratio of polarizability to ionization potential and with the number of carbon atoms in each target are investigated. Employing this correlation, the approximate polarizability volume of C4 to C6 formates has been computed for the first time.