Analysis of the laser photoelectron spectrum of CHminus;2

摘要

We have simulated the photoelectron spectrum of CHminus;2using the model described previously lsqb;Sears and Bunker, J. Chem. Phys.79, 5265 (1983)rsqb;. The optimization of the fit of the simulated spectrum to the recently observed spectrum of Lineberger and cohyphen;workers lsqb;J. Chem. Phys.81, 1048 (1984) and preceding paperrsqb; has enabled us to determine the rotationhyphen;bending energy levels of triplet CH2over an energy range of more than 1 eV. It has also enabled us to determine that the rotational temperature of the CHminus;2in the experiment is 220 K and that, forv2=1, the vibrational temperature is 680 K. For CHminus;2we determine thatae=103deg; and that ngr;2=1230 cmminus;1. The singletndash;triplet splitting in methylene is determined to be 3150plusmn;30 cmminus;1(0.3905plusmn;0.004 eV, 9.01plusmn;0.09 kcal/mol) from the photoelectron spectrum, in excellent agreement with the more accurate value previously obtained from LMR spectroscopy lsqb;McKellaretal., J. Chem. Phys.79, 5251 (1983)rsqb; of 3165plusmn;20 cmminus;1(0.3924plusmn;0.0025 eV, 9.05plusmn;0.06 kcal/mol), and the electron affinity of triplet CH2is determined to be 0.652plusmn;0.006 eV.