Molecular-frame photoelectron and electron-frame photoion angular distributions and their interrelation

General expressions for molecular frame photoelectron angular distributions (MFPAD) and the angular distributions of the recoil fragments relative to the electron emission direction, called 'the electron frame photoion angular distribution' (EFPAD), are analysed within the dipole approximation. We describe the projection methods as a tool to extract the maximum amount of information about MFPAD and EFPAD recorded by photoelectron-photoion coincidence momentum spectroscopy, using the N1s photoionization of NO at 412 eV as a specific example. Via a simulation of an experiment on EFPAD with electron detection in only two directions, we demonstrate the usefulness of the EFPAD and how to obtain full information on the EFPAD and MFPAD from such a restricted measurement of the EFPAD.