TY - JOUR
T1 - Dynamics of photoinduced reactions in hydrogen-bonded clusters
T2 - Classical studies of the photodissociation of (HCl)2
AU - McCoy, A. B.
AU - Hurwitz, Y.
AU - Gerber, R. B.
PY - 1993
Y1 - 1993
N2 - A theoretical investigation of the photodissociation dynamics of (HCl)2 at 193 nm is presented. Prior to excitation, the cluster is taken to be in its rotation-vibration ground state. A quantal description of this six-dimensional wave function is computed using diffusion quantum Monte Carlo (DQMC). The photodissociation dynamics are simulated by classical trajectories in which the molecule undergoes vertical excitation to an electronic state that is repulsive along one of the HCl stretch coordinates. The initial conditions for these trajectories are sampled according to the Wigner function which was obtained from the DQMC wave function. In a significant fraction of these trajectories, there is a reactive collision in which the H atom interacts with the H′Cl′ molecule to form HCl′. Of the remaining collisions, most are nonreactive, but a small number lead to H2 formation. The trajectories in which an exchange reaction occurs result typically in formation of HCl′ molecules that are rotationally and vibrationally hotter and in H atoms with lower kinetic energies than are found in the nonreactive trajectories. Resonances, in which the H atom undergoes multiple collisions with Cl and H′Cl′, are observed in all three classes of trajectories. The above results indicate that this is a rich system for the study of photoinduced chemical reactivity in hydrogen-bonded clusters.
AB - A theoretical investigation of the photodissociation dynamics of (HCl)2 at 193 nm is presented. Prior to excitation, the cluster is taken to be in its rotation-vibration ground state. A quantal description of this six-dimensional wave function is computed using diffusion quantum Monte Carlo (DQMC). The photodissociation dynamics are simulated by classical trajectories in which the molecule undergoes vertical excitation to an electronic state that is repulsive along one of the HCl stretch coordinates. The initial conditions for these trajectories are sampled according to the Wigner function which was obtained from the DQMC wave function. In a significant fraction of these trajectories, there is a reactive collision in which the H atom interacts with the H′Cl′ molecule to form HCl′. Of the remaining collisions, most are nonreactive, but a small number lead to H2 formation. The trajectories in which an exchange reaction occurs result typically in formation of HCl′ molecules that are rotationally and vibrationally hotter and in H atoms with lower kinetic energies than are found in the nonreactive trajectories. Resonances, in which the H atom undergoes multiple collisions with Cl and H′Cl′, are observed in all three classes of trajectories. The above results indicate that this is a rich system for the study of photoinduced chemical reactivity in hydrogen-bonded clusters.
UR - http://www.scopus.com/inward/record.url?scp=0000230207&partnerID=8YFLogxK
U2 - 10.1021/j100150a012
DO - 10.1021/j100150a012
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AN - SCOPUS:0000230207
SN - 0022-3654
VL - 97
SP - 12516
EP - 12522
JO - Journal of Physical Chemistry
JF - Journal of Physical Chemistry
IS - 48
ER -