LASER-STARK AND FOURIER TRANSFORM SPECTRA OF THE $v_{3}$ BAND OF FORMIC ACID

$^{1}$ H. Kuze, T. Amano, and T. Shimizu, J. Chem. Phys. 77, 714 (1982). Address of Weber and Maker: Physics Department, Research Staff, Ford Motor Company, Dearborn, MI 48121. Address of Johns: Herzberg Institute of Astrophysics, National Research Council of Canada, Ottawa, Canada K1A OR6Author Institution:The $5.6-\mu m$ band of HCOOH, which is the strong carbonyl stretch mode, is analyzed using a combination of sub-Doppler resolution laser-Stark data obtained with a Co laser and Fourier transform data obtained from a Bomem interferometer. The Fourier transform data, including 647 lines with $J' \leq 22$ and $K_{a}\leq 11$, are fit with a Watson type Hamiltonian to determine excited state constants. The Coriolis interactions with $v_{5+9}$ and $v_{6+9}$, previously noted by Kuze $et al.^{1}$, are included in the analysis; the former by using an exact diagonalization technique, the latter via perturbation theory. Taking the molecular parameters from this fit, the laser-Stark data are then analyzed to give ground and excited state dipole moments, yielding the following results in Debye: $\begin{array}{lll}\mu a^{\prime\prime} &=& 1.4071(8)\\\mu b^{\prime\prime}&=&0.227 (10)\\\mu a^{\prime}&=& 1.4353 (9)\\\mu b^{\prime} &=& 0.214 (9),\end{array}$ where the errors are $3\sigma$ estimates. The laser-Stark data are limited to $J'\leq 7$ and give $a\pm 14$ MHz fit to 191 lines