Laser Excitation Spectroscopy of theB̃2A1–X̃2A1Transition of the CaOCH3Radical

The A2E–X2A1 System of CaOCH3

“…After several iterations of this procedure, we were able to assign transitions for eight subbands from K = −3 to +4. Then, still keeping the ground state constants fixed, we combined our A 2 E-X 2 A 1 data with the B 2 A 1 -X 2 A 1 line measurements of Whitham et al (13) in a global fit to produce a consistent set of constants for the A and B states. All these constants are listed in Table 1.…”

“…Calcium species have drawn particular attention: CaOH should be abundant in circumstellar envelopes (7) and the question of its electric dipole moment has been the subject of both experimental (8) and theoretical (9) investigations. Marked similarities between spectra of linear CaOH and the Ca monohalides invited extension of these studies to CaR compounds of lower symmetries, in order to understand their electronic structure and bonding: for instance CaNH 2 (10) for C 2v , CaCH 3 (11) and CaOCH 3 (12,13) for C 3v . The C 3v species are of particular interest for Jahn-Teller studies, as shown in a recent review (14), because they give access to degenerate E electronic states where such vibronic interaction can take place.…”

“…(12) by optical Stark spectroscopy, while in Ref. (13) the B 2 A 1 -X 2 A 1 system of CaOCH 3 at 565 nm was analyzed by laser excitation spectroscopy, in both cases at a rotational resolution. There are at present no reports of highresolution studies of the A 2 E-X 2 A 1 system of CaOCH 3 in the literature, although several sequences of bandheads have been observed (15,16) and the frequencies of all the vibrational modes involving the Ca atom have been determined.…”

High-Resolution Laser Spectroscopy of the Ã2B2–X̃2A1 and B̃2B1–X̃2A1 Systems of SrNH2

“…These were recently reviewed by Bernath (1,2). The initial high-resolution studies of linear species such as halides and hydroxides were more recently extended to lower symmetry species such as the C 3v methyl (3) and methoxide (4,5) derivatives. Recently the bent CaSH molecule which has C s symmetry was analyzed (6,7).…”

Geometry of the CaOCH3 radical from isotope effects in the transition

“…The only conclusions we could draw were that there was a decrease in the Ca-O bond length on excitation from theX to the à state and that the CH 3 ''umbrella'' did not change significantly. Previous analyses of data for theB 2 A 1 -X 2 A 1 transition [2] had fixed the O-C and C-H bond lengths to values obtained from OCH 3 [3] and methanol [4], respectively, and had then determined the Ca-O bond length and the H Ĉ H bond angles for theX andB states.…”