Triple differential cross sections for the ionization of formic acid by electron impact

Theoretical triple differential cross sections for the simple ionization of the two outermost valence orbitals of formic acid monomer are given in this work. The first Born approximation is used to describe the collision dynamics with one Coulomb wave function for the ejected electron. Single-center molecular wave functions are generated using the Gaussian 09 program. The cross sections are calculated for an average molecular orientation with the proper average method. The results show that the proposed framework provides better agreement with experimental data than the previously used orientation averaged molecular orbital approximation. Consequently, this work shows the importance of performing the orientation averaging on the cross sections and not on the molecular wave functions. It also provides a methodology that reduces the complexity of calculations while maintaining a good quality of the results. (paper)