A new spectroscopic technique, giving complete two-dimensional e(-)-e(-) coincidence spectra in single photon double photoionization, is presented. The technique resolves the states of doubly charged ions and provides spectra of the individual electrons emitted in formation of each final dication state. Complete spectra for double photoionization of Xe, Kr, and Ar at photon energies up to 51 eV have been recorded. Overall and surprisingly, the np(4) 3P, 1D, and 1S states are populated according to their statistical weights. When the evident autoionization is excluded, the supposedly favored 3P states are in fact disfavored. Detailed information on the autoionization processes is also made available.

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The photodissociation of ozone at 226 nm is studied for O3→O2(X3 Σ−g)+O(2p3Pj) by probing O(3Pj) atomic photofragments with a resonance-enhanced multiphoton ionization method. Angular and kinetic energy distributions are determined by measuring time-of-flight spectra as a function of the angle between the polarization vector of the dissociation laser and the detector axis. The Doppler width of O(3Pj) photofragments is also measured. The translational energy distribution is well represented by assuming the formation of vibrationally excited O2 molecules with an average vibrational quantum number of 12. The anisotropy parameter β for the angular distribution is found to be 0.7±0.1. The predissociation dynamics from the photoprepared O3(1B2) state to the repulsive potential surface is discussed.

Using the VIPCO technique, we remeasured and completed the breakdown diagram of CCl(4) (+) up to 21 eV energy. The angle-resolved data show both orientation and alignment of photoelectrons relative to CX(3) (+) fragments from photoionization to the low-lying states of CF(4) (+) and CCl(4) (+). The strength of the orientation (forward/backward asymmetry) is surprising in view of the nearly spherical symmetry of the parent molecules, and calls for theoretical explanation. It may indicate that nuclear and electron motion take place on similar time-scales.