Equilibrium structure, vibrational frequencies, and ionization energies of the para-benzyne radical anion are characterized by coupled-cluster and equation-of-motion methods. Vibronic interactions with the low-lying excited state result in a flat potential energy surface along the coupling mode and even in lower-symmetry C_2v structures. Additional complications arise due to Hartree-Fock instabilities and near-instabilities.

To model angular distributions of photoelectrons, we implemented the calculation of Dyson orbitals using EOM-IP/EA-CCSD.

As a part of spectroscopy modeling unit of programs, we develop a code for wavepacket propagation.

Studies of alkyl and alkyl peroxy radicals to determine their contribution to ozone formation.

Ionization of liquid water is of great practical interest in the context of atmospheric and biological chemistry. The removal of an electron leads to cascade formation of reactive intermediates that can incur cellular damage. Despite several decades of research, the nature of the initially formed state and its immediate dynamics are still poorly understood. We pose a very fundamental question: "What does it mean to ionize water?"

The benzene dimer cation is a model system for ionized π-stacked aromatic molecules, which are thought to play an important role in charge transfer processes in biological systems (e.g. DNA). Using the EOM-IP method, we characterize the ten low-lying excited states of the benzene dimer cation and determine important relaxation coordinates.

Electronic states of the uracil dimer.

We investigated the highly debated three-body dissociation of sym-triazine to three HCN products, which depends on the topology of the excited states' potential energy surfaces.