Analysis of an 18O and D enhanced water spectrum and new assignments for HD18O and D218O in the near-infrared region (6000–7000 cm−1) using newly calculated variational line lists

Abstract An experimental infrared spectrum due to Orphal and Ruth (2008) [10] recorded using isotopically enriched water in the 6000–7000 cm −1 region is analysed and assigned. The assignment procedure is based on the use of known transition frequencies for H 2 16 O and H 2 18 O, existing variational line lists for HD 16 O and D 2 16 O, and newly calculated variational line lists for HD 18 O and D 2 18 O. These new variational line lists are presented herein. The main absorption comes from HD 16 O and HD 18 O, for which there are few previous assignments in the region. Assignments to 426 new HD 18 O lines are presented. In all 3254 of the 4768 lines observed in the spectrum are assigned, resulting in a number of newly determined energy levels. These assignments are in agreement with the recent work of Mikhailenko et al. (2012) [41] .