High resolution vacuum ultraviolet pulsed field ionization photoelectron band for OCS{sup +}(X{sup 2}{Pi}): An experimental and theoretical study
- Ames Laboratory, USDOE and Department of Chemistry, Iowa State University, Ames, Iowa50011 (United States)
- Chemical Sciences Division and Advanced Light Source, Accelerator and Fusion Research Division, Lawrence Berkeley National Laboratory, Berkeley, California94720 (United States)
- Theoretical Chemistry Group, Universite de Marne-la-Vallee, F-93166Noisy le Grand (France)
The vacuum ultraviolet pulsed field ionization photoelectron (PFI-PE) band for OCS{sup +}(X{sup 2}{Pi}) in the energy region of 11.09{endash}11.87 eV has been measured using high resolution monochromatized synchrotron radiation. The ionization energies (IEs) for the formation of the (0,0,0) X{sup 2}{Pi}{sub 3/2} and (0,0,0) {sup 2}{Pi}{sub 1/2} states of OCS{sup +} are determined to be 11.1831{plus_minus}0.0005 and 11.2286{plus_minus}0.0005eV, respectively, yielding a value of 367{plus_minus}1.2cm{sup {minus}1} for the spin{endash}orbit splitting. Using the internally contracted multireference configuration interaction approach, three-dimensional potential energy functions (PEFs) for the OCS{sup +}(X{sup 2}{Pi}) state have been generated and used in the variational Renner{endash}Teller calculations of the vibronic states. The energies of all vibronic states (J=P) for J=1/2, 3/2, 5/2, and 7/2 have been computed in the energy range of {approx}4000cm{sup {minus}1} above the IE[OCS{sup +}(X{sup 2}{Pi}{sub 3/2})] for the assignment of the experimental spectrum. By a minor modification of the {ital ab initio} PEFs, good correlations are found between the experimental and theoretical Renner{endash}Teller structures. Similar to the PFI-PE bands for CO{sub 2}{sup +}(X{sup 2}{Pi}{sub g}) and CS{sub 2}{sup +}(X{sup 2}{Pi}{sub g}), weak transitions have been detected in the PFI-PE band for OCS{sup +}(X{sup 2}{Pi}), which are forbidden in the Franck{endash}Condon approximation. The nonvanishing single-photon ionization cross sections involving the excitation of the bending vibrational modes of OCS{sup +}, CO{sub 2}{sup +}, and CS{sub 2}{sup +}, in their ground electronic states are attributed to the symmetries of the geometry-dependent electronic transition dipole operator components. {copyright} {ital 1998 American Institute of Physics.}
- OSTI ID:
- 625385
- Journal Information:
- Journal of Chemical Physics, Vol. 108, Issue 15; Other Information: PBD: Apr 1998
- Country of Publication:
- United States
- Language:
- English
Similar Records
Rotationally resolved pulsed field ionization photoelectron study of CO{sup +}(X{sup 2}{Sigma}{sup +},v{sup +}=0{endash}42) in the energy range of 13.98{endash}21.92 eV
Rotational-resolved pulsed field ionization photoelectron study of NO{sup +}(a {sup 3}{Sigma}{sup +},v{sup +}=0{endash}16) in the energy range of 15.6{endash}18.2 eV