High-Lying Rotational Levels of Water: Comparison of Calculated and Experimental Energy Levels for (000) and (010) up toJ= 25 and 21

High-Lying Rotational Levels of Water: An Analysis of the Energy Levels of the Five First Vibrational States

“…A redetermination of the rotational energy was therefore carried out for the ground and (010) states. We believe that for these states the energy values presented in the present paper are more accurate than those published previously (11). For the rotational levels dealt with in the present investigation as well as in our previous work (11), the root mean square (RMS) deviation of the difference between the energy obtained in our previous investigation (11) and those reported in the present work is 4.9 × 10 −3 cm −1 , the largest energy difference being 1.13 cm −1 for the (010) 21 14,8 level.…”

“…However, for higher J values, large discrepancies arise. For the ground and (010) states these were mentioned in our previous work (11). For the first triad states, differences on the order of 0.1 cm −1 can be observed.…”

“…Neglecting nondiagonal stretching-type matrix elements, as for Eq. [11], it can be shown that we also obtain three uncoupled equations,…”

“…In this investigation the methane-oxygen flame spectra used are the same as those which were recorded for our previous paper (11). The reader is referred to that paper for a detailed description of the experimental set-up.…”

“…For the same reason, the large rotational spacing makes it very difficult to carry out a thorough experimental investigation of the rotational energy, as only a small number of rotational levels are populated at room temperature. Techniques involving hot water spectra (2,4,5), flame spectroscopy (6)(7)(8)(9)(10)(11), or a long-path cell (12) must be used to access a sufficient number of rovibrational levels.…”