Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7846452 | Journal of Quantitative Spectroscopy and Radiative Transfer | 2017 | 12 Pages |
Abstract
The HITEMP2010 and HITRAN2012 databases are important tools for predicting molecular absorption under various environmental conditions. At room temperature, the databases can be quite accurate, owing to their development using room temperature absorption data. However, at elevated temperatures common to combustion and planetary research, their broadband accuracy is largely unexplored. We utilize a dual frequency comb spectrometer and a high temperature optical cell to assess the capability of these databases to accurately predict water vapor absorption for over 600 transitions at conditions up to 1300Â K from 6800Â cmâ1 to 7200Â cmâ1. We demonstrate that at 1300Â K, HITEMP2010 and HITRAN2012 accurately predict the existence and position (within 0.033Â cmâ1) of >99% of transitions with an intensity greater than 1Eâ28 (cmâ1/molecule cmâ2), which is the approximate minimum detectable intensity for our absorption spectra. Of the slightly less than 1% of transitions that are misreported, all have linestrengths below 1Eâ23 (cmâ1/molecule cmâ2). HITEMP more often predicts transitions that are not observed in the absorption spectra, while HITRAN more often fails to predict an observed line. Updated temperature-scaling coefficients for air-broadening and updated line assignments improve the high temperature performance of HITRAN compared to HITEMP for lineshapes and positions. Our analysis also shows that adding simple temperature-scaling relationships for air-pressure shift and self-broadening half width increase the predictive accuracy of simulations using both databases, and should be employed whenever transition-specific information is unavailable.
Related Topics
Physical Sciences and Engineering
Chemistry
Spectroscopy
Authors
P.J. Schroeder, D.J. Pfotenhauer, J. Yang, F.R. Giorgetta, W.C. Swann, I. Coddington, N.R. Newbury, G.B. Rieker,