The absorption spectrum of HDO in the 16 300-16 670 and 18 000-18 350 cm(-1) spectral regions

The absorption spectrum of HDO has been recorded by Intracavity Laser Absor ption Spectroscopy in the 16 300-16 670 and 18 000-18 350 cm(-1) spectral r egions corresponding to the weak 2v(2) + 4v(3) and v(2) + 5v(3) bonds, resp ectively. The v(2) + 5v(3) band centered at 18 208.434 cm(-1) was found alm ost isolated and has been satisfactorily reproduced in the frame of the eff ective Hamiltonian model. On the other hand, the 2v(2) + 4v(3) band at 16 4 56.201 cm(-1) is strongly perturbed as the (0 2 4) bright state is involved in a complex interaction scheme including the (1 0 4), (5 0 1), (1 5 2), a nd (1 11 0) states. The rovibrational assignment of these interacting state s was greatly helped by the high-accuracy ab initio predictions performed b y D. Schwenke and H. Partridge [J. Chem. Phys. 000-000 (2000)]. They could be partly modeled by an effective Hamiltonian which has allowed the assignm ent and reproduction of most of the observed transitions. (C) 2000 Academic Press.