Integral rate constant measurements of the reaction H +D2O → HD(v′, j′)+OD

Abstract

The reaction H+D2O was studied by intersecting a pulsed beam of HI with an effusive spray of D2O in a high vacuum chamber. Translationally hot H atoms were generated by UV photolysis of HI in the intersection volume, and the HD product of the reaction H+D2O was detected in a quantum-state-specific manner by (2+1) resonance-enhanced multiphoton ionization. Because the same UV laser beam was used to initiate the reaction and detect the product, the relative collision energy varied as a function of product state detected—∼2.8 eV for v′=0, ∼2.6 eV for v′=1, and ∼2.5 eV for v′=2. Under these conditions, approximately 35% of the available energy is partitioned into the internal modes of the HD product. For the products, the HD ‘‘new bond’’ receives 15 times more energy than the OD ‘‘old bond.’’ A significant amount of energy appears as HD vibration with v′=0 and 1 having comparable populations. The fraction of available energy partitioned into HD rotation, gR(v′), is found to be essentially independent of HD vibration. This invariance may be rationalized in terms of a counterbalancing of two mechanisms for rotational excitation of the HD product. We find qualitative agreement between recent quasiclassical trajectory calculations by Kudla and Schatz for the HD product internal-state distributions and the present experimental results.

Direct mapping of vibrational-specific angular distributions of the polyatomic reaction product: CN+D2→DCN+D

“…Several elegant experiments have beautifully elucidated this feature in a few benchmark systems. [6][7][8][9][10][11] Among these is the reverse reaction of this investigation, HϩHCN. [6][7][8] In conjunction with the theoretical advances, new insights into polyatomics reaction dynamics were gained and some general rules have started to be formulated.…”

The dynamics of the H+D2O→OD+HD reaction at 2.5 eV: Experiment and theory

“…A large body of experimental data is also available with which to compare theoretical predictions. The majority of this experimental work has been devoted to measuring quantum state populations and reaction cross-sections ͑or rate co-efficients͒ for the forward reaction between H atoms and either vibrationally cold [30][31][32][33][34][35] or vibrationally excited [35][36][37] water molecules. The molecular frame alignment of vibra-tionally excited H 2 O molecules generated by inelastic scattering between thermal water molecules and translationally excited H atoms has also been observed by Leone and co-workers.…”

The Dynamics of the H+H2O Reaction

“…*: Using the OC PES; [75] &: using the YZCL2 PES. [78] have been measured by Adelman et al [80] using the ResonanceEnhanced Multiphoton Ionization (REMPI) technique. The HD product vibrational distribution P v' was 0.47 for v' 0, 0.45 for v' 1, and 0.08 for v' 2, which is in good agreement with the QCT distributions calculated recently on the WSLFH PES.…”