We report the infrared absorption spectrum of the OT stretch of 0.3% HOT in H2O. The absorption line shape has a peak at omega(*) = 2121 cm(-1) and line width of Delta omega = 127 cm(-1) (FWHM). Reduced mass scaling relationships for frequency, line width, and extinction coefficient are tested by comparing to omega(OH) and omega(OD) absorption spectra. Harmonic scaling relationships are found to be inadequate, and deviations are discussed in terms of electrical and mechanical anharmonicity. The inverse scaling of line width with the square root of reduced mass provides further evidence that electric field fluctuations properly describe the line broadening. (c) 2007 Elsevier B.V. All rights reserved.