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Observation of the c 1A1 state of methylene by optical-optical double resonance.
- Source :
- Journal of Chemical Physics; 7/8/2005, Vol. 123 Issue 2, p024306, 4p, 2 Diagrams, 2 Charts, 1 Graph
- Publication Year :
- 2005
-
Abstract
- We report the observation of the rotationally resolved spectrum of the c <superscript>1</superscript>A<subscript>1</subscript> state of CH<subscript>2</subscript> via sequential single-photon absorptions at visible and near-infrared wavelengths. Direct absorption from the lowest singlet state ã <superscript>1</superscript>A<subscript>1</subscript> to c <superscript>1</superscript>A<subscript>1</subscript> occurs in the near UV, but it is weak because it corresponds to a two electron transition between the dominant single configuration approximations to the electronic wave functions. Some absorption lines in the c-ã system were originally reported in 1966 [G. Herzberg and J. W. C. Johns, Proc. R. Soc. London, Ser. A 295, 107 (1966)], but the weak spectra could not be assigned at the time. Interest in the c <superscript>1</superscript>A<subscript>1</subscript> state was rekindled by recent ab initio results [S. N. Yurchenko, P. Jensen, Y. Li, R. J. Buenker, and P. R. Bunker, J. Mol. Spectrosc. 208, 136 (2001)] which prompted the present work. The new spectra provide accurate energies for rotational levels in the v<subscript>2</subscript><superscript>linear</superscript>=11,l=1 level of the state, and permit assignment of most of the line positions measured by Herzberg and Johns. The double-resonance technique used may be easily extended to the measurement of lower rovibrational levels in the electronic state and possibly also to access the d <superscript>1</superscript>A<subscript>2</subscript> state which is theoretically expected to lie at similar energies but, for symmetry reasons, is not accessible from the lowest singlet state in a single electric-dipole transition. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00219606
- Volume :
- 123
- Issue :
- 2
- Database :
- Complementary Index
- Journal :
- Journal of Chemical Physics
- Publication Type :
- Academic Journal
- Accession number :
- 17741050
- Full Text :
- https://doi.org/10.1063/1.1988289