| Autor: |
Grütter, M., Michaud, J. M., Merkt, F. |
| Předmět: |
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| Zdroj: |
Journal of Chemical Physics; 2/7/2011, Vol. 134 Issue 5, p054308, 12p, 4 Charts, 4 Graphs |
| Abstrakt: |
The high-resolution single-photon pulsed-field-ionization zero-kinetic-energy photoelectron spectra of the X+ 2E3/2←X 1A1 transition of CH3I and CD3I have been recorded. The spectral resolution of better than 0.15 cm-1 enabled the observation of the rotational structure. CH3I+ and CD3I+ are subject to a weak Exe Jahn-Teller effect and strong spin-orbit coupling. The treatment of the rovibronic structure of the photoelectron spectra in the corresponding spin double group, C3v2(M), including the effects of the spin-orbit interaction and the vibrational angular momentum, allowed the reproduction of the experimentally observed transitions with spectroscopic accuracy. The relevant spin-orbit and linear Jahn-Teller coupling parameters of the X+ ground state were derived from the analysis of the spectra of the two isotopomers, and improved values were obtained for the adiabatic ionization energies [EI(CH3I)/hc=76931.35(20) cm-1 and EI(CD3I)/hc=76957.40(20) cm-1] and the rotational constants of the cations. Rovibronic photoionization selection rules were derived for transitions connecting neutral states following Hund's-case-(b)-type angular momentum coupling and ionic states following Hund's-case-(a)-type coupling. The selection rules, expressed in terms of the angular momentum projection quantum number P, account for all observed transitions and provide an explanation for the nonobservation of several rotational sub-bands in the mass-analyzed threshold-ionization spectra of CH3I and CD3I reported recently by Lee et al. [J. Chem. Phys. 128, 044310 (2008)]. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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