Project Descriptions:

Potential Energy Surfaces

Solvated Species

CH₅⁺

Porous Crystalline Species

Temperature Effects on Structure

Photodissociation Dynamics

Computational Drug Design

Osteoporosis

Hydrogen Bonding

Photodissociation

Deborah Crittenden, Keiran Thompson
(A/Prof Scott Kable, Sydney)

We have calculated the first accurate PES for the photodissociation of T₁ acetaldehyde, a reaction important in atmospheric pollution. Dynamical calculations on this PES agree well with experiment and provide the first theoretical demonstration of reaction dynamics undergoing a transition from impulsive to statistical behaviour in the product state distributions as excess energy increases. Our calculations have also resolved a number of discrepancies in previous experimental and theoretical studies of this system.

We will continue our joint experimental and theoretical investigations of acetaldehyde, looking at dissociation on the ground state surface. We plan to characterize the dynamical signatures of the “roaming atom” mechanism in product state distriubutions. This mechanism describes reactions that proceed via a long-lived complex . Although such a mechanism is well known in ion-molecule reactions (and in theoretical calculations) it has only recently been characterized in the unimolecular dissociation of an uncharged species.

Selected Publications:

K. C. Thompson, D. L. Crittenden, S. H. Kable and M. J. T. Jordan "Theoretical Investigations of the Photodissociation of T₁ Acetaldehyde: CH₃OH ® CH₃ + HCO", J. Chem. Phys., 124, 044302 (2006). pdf (277 kB)