Molecular frame photoelectron angular distributions in inner valence photoionisation of CO
Abstract
The velocity imaging photoionisation coincidence (VIPCO) technique is applied to the photoionisation of CO into the inner-valence 4 2Σ+ state of CO+, and the molecular frame photoelectron angular distributions are measured on the high energy side of the known σ* shape resonance. The angular distributions at 40.8 and 48.4 eV show that partial waves with the angular momentum l⩽3 provide the dominant contribution to both parallel and perpendicular transitions, and the contributions from the l4 partial waves are relatively negligible. By restricting the partial wave expansion to l⩽3, eight and four sets of dipole