High sensitivity ICLAS of H218O between 13 540 and 14 100 cm-1

The high resolution absorption spectrum of 180 enriched water was recorded between 13 540 and 14 100 cm(-1) by high sensitivity Intracavity Laser Absorption Spectroscopy (ICLAS). This spectral region corresponds to the relatively strong 4v polyad. Four isotopologues of water ((H2O)-O-18, (H2O)-O-16, (H2O)-O-17, (HDO)-O-18) are found to contribute to the spectrum. About 1800 (H2O)-O-18 lines were assigned by comparison with variational calculations. Altogether, 855 accurate energy levels of (H2O)-O-18 were determined from transitions attributed to 23 upper vibrational states, 342 of them being reported for the first time. New information includes 84 energy levels of (H2O)-O-17 present with a 1.5% relative concentration in the sample and the rotational structure of the 4v(3) band of (H2O)-O-18 at 13814.520 cm(-1). By comparison with variational calculations and with ICLAS absolute intensity values, a systematic overestimation by about 25% has been evidenced for the (H2O)-O-18 intensity values included in the HITRAN database for the 12400-14 520 cm(-1) range. (C) 2011 Elsevier Inc. All rights reserved.