Communication: Determination of the bond dissociation energy (D0) of the water dimer, (H2O)2, by velocity map imaging

The bond dissociation energy (D-0) of the water dimer is determined by using state-to-state vibrational predissociation measurements following excitation of the bound OH stretch fundamental of the donor unit of the dimer. Velocity map imaging and resonance-enhanced multiphoton ionization (REMPI) are used to determine pair-correlated product velocity and translational energy distributions. H2O fragments are detected in the ground vibrational (000) and the first excited bending (010) states by 2 + 1 REMPI via the (C) over tilde B-1(1) (000) <- (X) over tilde (1)A(1) (000 and 010) transitions. The fragments' velocity and center-of-mass translational energy distributions are determined from images of selected rovibrational levels of H2O. An accurate value for D-0 is obtained by fitting both the structure in the images and the maximum velocity of the fragments. This value, D-0 = 1105 +/- 10 cm(-1) (13.2 +/- 0.12 kJ/mol), is in excellent agreement with the recent theoretical value of D-0 = 1103 +/- 4 cm(-1) (13.2 +/- 0.05 kJ/mol) suggested as a benchmark by Shank et al. [J. Chem. Phys. 130, 144314 (2009)]. (c) 2011 American Institute of Physics. [doi:10.1063/1.3598339]