Complete unambiguous spectroscopic labeling of rotational levels of 000, 010, 100, 020, and 001 vibrational states of H218O up to J, Ka = 30 is presented and discussed. The levels to be labeled were calculated with Partridge and Schwenke empirical function of potential energy surface. Labeling was done by fitting parameters of a generating-function rotational Hamiltonian to calculated energies. Comparison of assigned calculated levels with experimental levels collected from the literature is given. Comparison of PS and Shirin et al. calculated levels is also presented and discussed. Obtained results will be useful to search and identify new high-exited states of H218O.
water molecule; vibrational-rotational spectra; identification; assigning; Partridge-Schwenke