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The spectrum of CH2 near 1.36 and 0.92 μm: Reevaluation of rotational level structure and perturbations in ã(010).

Authors :
Kobayashi, Kaori
Hall, Gregory E.
Sears, Trevor J.
Source :
Journal of Chemical Physics; 5/14/2006, Vol. 124 Issue 18, p184320, 10p, 6 Charts, 2 Graphs
Publication Year :
2006

Abstract

The spectrum of methylene in the 1.3–1.4 and 0.89–0.94 μm wavelength regions has been recorded in absorption using frequency-modulated cw diode and Ti:sapphire laser sources. The spectral lines have Doppler-limited resolution and have been assigned to bands in the b <superscript>1</superscript>B<subscript>1</subscript>←ã <superscript>1</superscript>A<subscript>1</subscript> electronic spectrum of the radical. In three of the four bands studied, the lower state is the bend excited, υ<subscript>2</subscript><superscript>″</superscript>=1, level of the ã state and two of the upper levels lie below the energy of the degenerate linear configuration of the b/ã pair. Together with previously measured data pertaining to υ<subscript>2</subscript><superscript>″</superscript>=1, the data have been used to refine the precision of the experimentally determined rotational structure in this level. Although several K<superscript>″</superscript>=1 levels do show shifts of more than 0.1–0.2 cm<superscript>-1</superscript>, multiple strong perturbations due to near-resonant background X <superscript>3</superscript>B<subscript>1</subscript> rovibrational levels, such as are known to occur in the ã <superscript>1</superscript>A<subscript>1</subscript>, υ<subscript>2</subscript><superscript>″</superscript>=0 level have not been found in υ<subscript>2</subscript><superscript>″</superscript>=1. Absorption lines due to the predominantly triplet X(040) 4<subscript>14</subscript> level, responsible for most of the perturbation of ã(010) 5<subscript>15</subscript>, have been identified in the spectra. The data also fix the energies of the b(0,0,0)<superscript>2</superscript>, ã(0,7,0)<superscript>1</superscript>, b(0,2,0)<superscript>3</superscript>, and ã(0,10,0)<superscript>2</superscript> upper vibronic levels, where the numbers in parentheses are the vibrational quantum numbers with superscript K, the projection of the total angular momentum on the a-inertial axis. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
00219606
Volume :
124
Issue :
18
Database :
Complementary Index
Journal :
Journal of Chemical Physics
Publication Type :
Academic Journal
Accession number :
20924173
Full Text :
https://doi.org/10.1063/1.2200340