Current results and perspectives on the dynamics of photoionization of small molecules
obtained from the analysis of Molecular Frame (MF) photoemission are reviewed. The MF observables
intrinsically couple the ionized molecular orbital and the scattering wave function of the photoelectron
in the ionization continuum. The field of molecular photoionization has benefited from the development
of experimental methods based on the determination of electron-ion momentum vector correlations
using position and time sensitive detectors, as well as from advanced ab initio calculations accounting
for electronic correlations which influence the different steps of a photoionization reaction. Key
features of valence shell and inner shell photoionization processes, involving resonant and non-resonant
mechanisms, are illustrated for small molecules of increasing complexity: we emphasize the general
formalism which describes molecular frame photoemission for single ionization of linear molecules
induced by linearly and elliptically polarized light after one photon absorption, and its extensions to
recoil frame photoemission when non-linear molecules or multiphoton processes are considered. The
rich information contained in molecular frame photoemission is at the core of a number of recent
experiments at the forefront of molecular physics.
