Infrared spectroscopy of tritiated water

PHYS 328

Rebecca A. Nicodemus, nicodemu@mit.edu, Lauren DeFlores, and Andrei Tokmakoff, tokmakof@MIT.EDU. Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02139
Studies of water with ultrafast nonlinear infrared spectroscopy have commonly used isotopically dilute solutions, which provide a local probe of hydrogen bond dynamics. We have studied the infrared spectroscopy of tritiated water, as a step toward probing hydrogen bond switching with correlation spectroscopy between the OD and OT stretching vibrations in H2O. We report on the infrared absorption spectrum and femtosecond infrared pump-probe spectroscopy of the OT stretching vibration of HOT in H2O. We compare IR absorption line shape parameters between the three isotopes (OH:OD:OT), discussing deviations from harmonic scaling relationships in terms of electrical and mechanical anharmonicity. Comparison of the lifetimes between the three isotopes, obtained from pump-probe experiments, gives valuable information on the vibrational relaxation pathways in water.