High-lying rotational levels of water: An analysis of the energy levels ofthe five first vibrational states

As a continuation of the work carried out on the ground and (010) vibration al states of water (R. Lanquetin, L. H. Coudert, and C. Camy-Peyret, 1999, J. Mol. Spectrosc. 195, 54-57), rotational energy levels for these two stat es are revisited here and new accurate rotational energy levels are conside red for the three next vibrational states, that is, the (020), (100), and ( 001) states. Experimental rotational energies, along with their uncertainti es, are retrieved through analyses of already published data sets and of di scharge and flame emission spectra. The maximum value of J for the obtained levels is 25 for the ground state, 21 for the (010) state, and 20 for the three next states. Based on the bending-rotation Hamiltonian approach (L. H . Coudert, 1997. J. Mel. Spectrosc. 181, 246-273), a new theoretical approa ch is proposed to calculate rotational energies in the five interacting vib rational states under consideration and is used to carry out an analysis of the experimental energies. Comparisons with other existing energy level da ta sets are also presented. (C) 2001 Academic Press.