Laser magnetic resonance spectrum of 13CH2 around 11 µm: determination of 13C hyperfine interactions and ν2 isotope shift for methylene

Abstract

Ten rotation–vibration transitions of the ν2 (bending) fundamental band of 13CH2 have been observed using the technique of CO2 laser magnetic resonance in the 880 to 945 cm−1 region. 13C substituted methylene was produced in a flow system by reacting 13CH4 or 13CH2CO with F atoms from a microwave discharge in CF4. Analysis of the spectra yields a number of molecular parameters for 13CH2. Specifically, the 13C isotope shift of ν2 is −3.93 cm−1 and the 13C Fermi contact hyperfine parameter is 238 ± 6 MHz for the ground vibrational state. The hyperfine parameters determined here for gas phase 13CH2 are in fairly good agreement with those determined for matrix isolated 13CD2 in earlier ESR experiments.