Vibrational relaxation and spectral evolution following ultrafast OH stretch excitation of water

Ultrafast anti-Stokes Raman measurements of OH stretching excitations (3000–3600 cm−1) in water show an ∼0.4 ps spectral evolution from the red to the blue that is similar to what is seen in the Raman spectrum of water heated to 90 °C. The lifetime of OH stretching excitations T1=0.7 ps. A small portion of the spectrum on the blue edge of the band decays more slowly with T1=1.1 ps. A previous measurement of T1≈0.3 ps for water [J. Chem. Phys. 117 (2002) 1708] is reinterpreted shown to consistent with the present work.