Photoionization-Efficiency Studies of Some Simple Inorganic Molecules

摘要

High resolution (0.14 A FWHM) photoionization efficiency (PIE) measurements of HgCl sub 2+ , HgBr sub 2+ , and HgI sub 2+ have been obtained by the supersonic molecular beam method. This study has yielded more precise values of the ionization energies (IEs) of the exp 2 Pi/sub 3/2g/, exp 2 Pi/sub 1/2g/, and exp 2 D/sub +-5/2/ states of HgX sub 2+ (X = Cl, Br, and I) to within +- 3 MeV. Lower resolution (1.4 A FWHM) studies of the HgX sub 2 fragment ions have been undertaken and values of the binding energies of HgX exp + and HgX have been calculated from the measured appearance energies (AEs) of HgX exp + and X exp + . In addition, PIE studies of the CO sub 2 , N sub 2 O, CO, N sub 2 , NO, and O sub 2 dimers and clusters have been performed, yielding the IEs of (CO sub 2 )/sub n=2-4/, (N sub 2 O) sub 2 , (CO)/sub n=2,3/, (N sub 2 )/sub n=2,3/, and (NO)/sub n=2-6/, and the AEs of N sub 2 O sub 3+ from (N sub 2 O) sub 2 , O sub 3+ from (O sub 2 ) sub 2 , O sub 5+ from (O sub 2 ) sub 3 , and O sub 7+ from (O sub 2 ) sub 4 . Analysis of the PIE curves of (CO sub 2 ) sub 2+ and (N sub 2 O) sub 2+ indicates that electronic predissociation may be an important dissociation mechanism for the CO sub 2 */sub (n)/.CO sub 2 and N sub 2 O*/sub (n)/.N sub 2 O Rydberg dimers. From the IEs of (NO)/sub n/, n=1-6, solvation energies of NO exp + by one to five NO molecules have been determined. By analysis of the PIE spectra for O sub 3+ , O sub 5+ , and O sub 7+ , and by comparing their relative intensities, insights concerning the internal energy effects on ion-molecule half reactions have been obtained. (ERA citation 08:016495)