Non-resonant breakdown of the Franck-Condon approximation as seen in vibrational branching ratios

Abstract

We consider vibrational branching ratios in the valence photoionization of N2, CO, and XCN, with X=F, Cl, Br, and I. Non-resonant geometry dependence of the matrix elements is seen to lead to the breakdown of the Franck-Condon approximation. The geometry dependence can be due to changing molecular orbitals or changing nodal positions in the continuum wave functions. © Published under licence by IOP Publishing Ltd.