High-lying rotational levels of water: Comparison of calculated and experimental energy levels for (000) and (010) up to J = 25 and 21

Emission spectra of methane-oxygen low-pressure flames have been recorded a t a resolution of 0.02 cm(-1) with an infrared Fourier transform spectromet er in the spectral ranges 780-1370 and 1800-5000 cm(-1). The flame temperat ure was about 1850 K and a large number of transitions involving J values a s high as 34 for an extended set of vibrational states could be assigned. C ombined with already published data sets on H2O, our line position analysis yielded rotational energy levels for many of these states, but only the re sults relevant to the ground and the (010) states are presented here. The e xperimental energies for these two states have been fitted with the help of the bending-rotation Hamiltonian approach [L. ii. Coudert, J. Mol. Spectro sc. 181, 246-273 (1997)], and for each rotational level, the calculated ene rgy along with its uncertainty is reported and compared with the observed v alue. Comparisons with other available energy level data sets for the groun d and (010) states are also presented, (C) 1999 Academic Press.