Molecular beam photoionization spectrometry (1) photoionization studies of high temperature vapors (2) state-selected and state-to-state studies of electron transfer reactions

Abstract

<p>Photoionization efficiency studies of high temperature vapors (S(,2), Hg(,2), HgKr, HgXe) have been performed using the supersonic oven beam method. These studies have yielded precise values of ionization energies of S(,2), Hg(,2), HgKr and HgXe and appearance energy for dissociative ionization S(,2) + h(nu) (--->) S('+) + S + e('-). Dissociation energies of S(,2), S(,2)('+), Hg(,2)('+), HgKr('+) and HgXe('+) and equilibrium bond distances of HgKr and HgXe have been calculated. Two Rydberg series converging to the (')b('4)(SIGMA)(,g)('-) state of S(,2)('+) have been observed. Window resonances resolved in the region of 650-850 (ANGSTROM) have been assigned as members of Rydberg series converging to the c('4)(SIGMA)(,u)('-) and ('2)(PI)(,u) (or ('2)(SIGMA)(,u)('-)) states of S(,2)('+), respectively;A new ion-neutral reaction apparatus, which combines high resolution spectrometry, crossed ion-neutral beam method and charge transfer detection, has been developed to examine the energy effects on the total charge transfer cross sections for the reaction H(,2)('+)(v(,o)') + H(,2)(v(,o)'' = 1) (--->) H(,2)(v') + H(,2)('+)(v''). The vibrational state distributions of product H(,2)('+)(v'') ions in collision energy range of E(,c.m.) = 2-16 eV have been determined by the charge exchange method. A state-to-state study of fine-structure transitions in Ar('+)(('2)P(,J)) + Ar(('1)S(,o)) charge transfer collisions have been performed. The spin-orbit effects on the charge transfer cross sections and kinetic energy dependences for the fine-structure transition probability (('2)P(,3/2) (--->) ('2)P(,1/2)) are in general agreement with the theoretical predictions. The experimental results are consistent with the condition of detailed balance for fine-structure transitions;in the charge transfer collisions at collision energies substantially greater than the spin-orbit splitting of Ar('+); *USDOE Report IS-T-1194. This work was performed under Contract No. W-7405-Eng-82 with the U.S. Department of Energy.</p>