High-temperature rotational transitions of water in sunspot and laboratory spectra

Assignments are presented for spectra of hot water obtained in absorption in sunspots (T similar to 3000 degrees C and 750 equal to or less than <(nu)over tilde> equal to or less than 1010 cm(-1)) and in emission in the laboratory (T similar to 1550 degrees C and 370 equal to or less than <(nu)over tilde> equal to or less than 930 cm(-1)). These assignments are made using variational nuclear motion calculations based on a high-level ab initio electronic surface, with allowance for both adiabatic and nonadiabatic corrections to the Born-Oppenheimer approximation. Some 3000 of the 4700 transitions observed in the laboratory spectrum are assigned as well as 1687 transitions observed in the sunspot spectrum. All strong lines are now assigned in the sunspot measurements. These transitions involve mostly high-lying rotational levels within the (0,0,0), (0,1,0), (0,2,0), (1,0,0), and (0,0,1) vibrational states. Transitions within the (0,3,0), (0,4,0), (1,1,0), (0,1,1), (0,2,1), (1,1,1), (1,2,0), and (1,0,1) states are also assigned. For most bands the range of K-a values observed is significantly extended, usually doubled. New features observed include numerous cases where the closely degenerate levels J(K?aK?c), and J(K?aK?c+1) with high K-a are split by Coriolis interactions. Comparisons are made with the recent line list of Partridge and Schwenke (1997, J. Chem. Phys. 106, 4618). (C) 1997 Academic Press.