Vibrational Transition Moment of the CH Radical Determined from the Herman‐Wallis Effect

Abstract

The Δ v = 1 emission spectrum of the CH radical was observed by a Fourier transform spectrometer. The Herman-Wallis effect observed as intensity difference in P - and R -branch transitions was analyzed to give the transition dipole moment, where we used a new method to calculate intensities of vibration-rotation spectral lines with wave functions obtained by the diagonalization of a vibration-rotation energy matrix up to v = 40. When the permanent dipole moment of 1.46 D was used, the vibrational transition moment μ 10 was determined to be -0.151(10) D, with 1 standard deviation in parentheses.