Knowledge Bank

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 $J\prime \le 22$ and $Ka\le 11$, are fit with a Watson type Hamiltonian to determine excited state constants. The Coriolis interactions with $v5+9$ and $v6+9$, previously noted by Kuze $etal.1$, 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: $\mu a\prime \prime =1.4071(8)\mu b\prime \prime =0.227(10)\mu a\prime =1.4353(9)\mu b\prime =0.214(9),$ where the errors are $3\sigma$ estimates. The laser-Stark data are limited to $J\prime \le 7$ and give $a\pm 14$ MHz fit to 191 lines.