Photo double ionization spectra of CO: comparison of theory with experiment

Abstract

High level ab initio calculations have been undertaken of potential energy curves of CO 2+ (and for the CO neutral ground state). The accuracy of the potentials was tested by a synthesis of the available vibrationally resolved threshold photoelectrons in coincidence (TPEsCO) and time of flight, photo electron photo electron coincidence (TOF-PEPECO) spectra of CO 2+ . Good agreement was found between experimental and theoretical spectra once relative energies of the calculated double ionization energies were slightly adjusted (by approximately 1%) to match experiment. Vibrational separations within individual electronic states are very well reproduced (the worst error is 0.07%).

Potential energy curves for neutral and multiply charged carbon monoxide

“…Hence it is expected to play an important role in the dissociation process. These observations are in accord with the earlier reported results [12,13]. The equilibrium bond lengths for 1 Σ + and 3 Π state are found to be 1.…”

“…The equilibrium bond lengths for 1 Σ + and 3 Π state are found to be 1. MRCI level with a different basis set than ours for 1 Σ + and 3 Π states have yielded r e = 1.226 and 1.138Å, respectively; ω e = 1920 and 1435 cm −1 , respectively [13]. The values of vertical ionization energy (I 2 ) for the 1 Σ + and 3 Π electronic states are 41.11 and 41.39 eV, respectively.…”

“…Experimental and theoretical results available on multiply charged ions have been reviewed elsewhere [9,10]. Although both mono and dications of CO have been investigated extensively [11][12][13][14][15][16][17][18], very few theoretical results are available on trication [19,20]. To the best of our knowledge, there is only one unrestricted Hartree-Fock and MP2 calculation reported for higher charged CO [8].…”

Density functional study of double ionization energies

“…Recent developments [11][12][13][14] of time-of-flight photoelectron-photoelectron coincidence technique for double photoionization spectroscopy have provided many new vertical DIEs. Therefore, we focus our attention only on the DIEs to the ground-state dications in this work, in contrast to previous theoretical studies, 15,16 which have been mainly concerned with interpretation of Auger spectra involving many dicationic states.…”

Kinetic energy release in fragmentation processes following electron emission: A time-dependent approach

“…Potential curves, shown in Fig. 1, are taken from a real example [24,25] to show the physics clearly. For a small Γ like 9.5 meV, the mirror image of the electron spectrum coincides with the KER spectrum, see the open circles and the red curve.…”