Circular dichroism is a consequence of chirality. However, nonchiral molecules can also exhibit it when the measurement itself introduces chirality, e.g., when measuring molecular-frame photoelectron angular distributions. The few such experiments performed on homonuclear diatomic molecules show that, as expected, circular dichroism vanishes when the molecular-frame photoelectron angular distributions are integrated over the polar electron emission angle. Here we show that this is not the case in resonant dissociative ionization of H2 for photons of 30-35 eV, which is the consequence of the delayed ionization from molecular doubly excited states into ionic states of different inversion symmetry.

We propose a method, molecular polarimetry, applicable to an extended VUV-x-ray range, allowing us to determine the complete state of elliptically polarized light, including the challenging disentanglement of the circular and unpolarized components. It relies on the determination of the molecular frame photoelectron angular distributions derived from electron-ion velocity vector correlations in dissociative photoionization of simple molecules. The high accuracy of the full set of Stokes parameters determination has been established by comparison with data obtained in parallel with a VUV optical polarimeter used as a benchmark.