A high-accuracy computed water line list

A computed list of H₂¹⁶O infrared transition frequencies and intensities is presented. The list, BT2, was produced using a discrete variable representation two-step approach for solving the rotation-vibration nuclear motions. It is the most complete water line list in existence, comprising over 500 million transitions (65percent more than any other list) and it is also the most accurate (over 90percent of all known experimental energy levels are within 0.3cm^-1 of the BT2 values). Its accuracy has been confirmed by extensive testing against astronomical and laboratory data.

The line list has been used to identify individual water lines in a variety of objects including comets, sunspots, a brown dwarf and the nova-like object V838 Mon. Comparison of the observed intensities with those generated by BT2 enables water abundances and temperatures to be derived for these objects. The line list can also be used to provide an opacity for models of the atmospheres of M dwarf stars and assign previously unknown water lines in laboratory spectra.