SPECTROSCOPY FOR THE C-O STRETCH BAND OF $CH_{3}OH$ USING $CO_{2}$ LASERS

Abstract

The C-O stretch band of $CH_{3}OH$ has been studied by combined use of microwave sideband spectroscopy and laser rf double resonance spectroscopy both using $CO_{2}$ lasers. A microwave modulator of $CO_{2}$ laser generates sidebands with frequencies of 8-18 GHZ and an out put of a few milliwatts. By using this radiation source, transition frequencies can be measured with an accuracy of 3 Mhz or better. Laser-rf double resonance technique enables us to observe rf transitions between Stark components for Stark tuned infrared lines, which is useful both for the determination of a dipole moment component, $\mu_{a}$, and for the assignment of infrared transitions. By using these two methods, the low-J energy levels of $E, \nu_{t} = 1, k= -1$, and k= 2 in the excited C-O stretch vibrational state have been determined accurately. The values of $\mu_{a}$ have been also determined for various states in this vibrational state.