- Multi-reference coupled cluster method. This topic is one of the central issues in current Quantum Chemistry. The development of an effective multi-reference coupled-cluster method will enable us to perform very accurate calculations on electronic states which can not be approximated by a single-determinant Hartree-Fock wave function. This important class of states includes some excited states (e.g. open-shell singlets) and states of systems undergoing geometrical transformations (e.g. transition states).

-Method for generating non-adiabatic multiparticle wave functions. The non-adiabatic approach to molecules has been considered by only a few research groups and remains one of the most challenging frontiers in Quantum Chemistry. We have recently proposed a method for determining the wave function describing the collective motion of nuclei and electrons. The method utilizes explicitly correlated Gaussian-type functions. Further development will concern stationary and nonstationary nonadiabatic excited states of molecular systems with up to six electrons.

- Methods for calculating rovibrational states of polyatomic molecules. Here we also utilize correlated gaussians with angular components. We are particularly interested in highly excited states near the dissociation and in the dynamics of the vibrational energy redistribution.

The method development is closely correlated with our interests, in phenomena, concerning: Ground and excited states of dipole bound molecular anions; Double Rydberg anions; Ground and excited states of molecular cluster anions; Non-adiabatic effects in molecular anions; Electron transfer reactions; Photochemistry in nucleic acid bases and their derivatives, fullerenes and nanotubes, etc.

A very important component of my research has been collaboration with experimental groups. The areas where our theoretical studies were used in conjunction with experimental efforts include the following: IR gas and matrix isolation spectroscopy of nucleic acid bases and their derivatives and complexes; UV spectroscopy of carbon clusters; Microwave spectroscopy of Van der Waals molecular complexes; IR spectroscopy of the hyperfine structure; Electron momentum spectroscopy; Rydberg electron transfer spectroscopy of dipole bound anions.

Dipole-bound electron in the anion of N-methyl-aminoadenine water complex.

- Methods for modeling charge and energy transport in extended molecular systems. The aim here is to describe the dynamics of the transfer process of electrons and holes in systems modeled after DNA or proteins. Charge transfer in these types of molecules can be viewed as a concerted motion of a local vibrational excitation and a localized wave packet describing temporary states of excess electrons/holes (exciton-polaron model). Based on this model we have developed and implemented a computational molecular method for simulating electron transfer in DNA. The work on refining the model and on extending its application to other biological systems (for example, polypeptide-based molecular wires) continues. The effort is also related to our interest in the phenomena of vibrational energy redistribution and transfer in biological systems. The study of the electrical conductivity of molecular wires based on biological systems is related to their potential application as interconnects in nano-electronics.

• I.D. Reva, S.G. Stepanian, L. Adamowicz, and R. Fausto, Conformational Behavior of Cyanoacetic Acid: A Combined Matrix Isolation Fourier Transform Infrared Spectroscopy and Theoretical Study, J.Phys.Chem., 107, 6351 (2003).A.F. Jalbout, K.Y. Pichugin, and L. Adamowicz, An Excess Electron Trapped Between Thymine and Adenine. Ab initio study, Chem. Phys. Lett., 376, 799, (2003).

• S.G. Stepanian, V.A. Karachevtsev, V.Y. Glamazda, U.D. Weglikowska, and L. Adamowicz, Combined Raman Scattering and ab-initio Investigation of the Interaction Between Pyrene and Carbon SWNT, Mol. Phys., 101, 2609, (2003).

• I.D. Reva, S.G. Stepanian, L. Adamowicz, and R. Fausto, Missing Conformers. Comparative Study of the Conformational Cooling in Cyanoacetic Acid and Methyl Cyanoacetate Isolated in Low Temperature Inert Gas Matrixes, Chem. Phys. Lett., 374, 631 (2003).

• R. Ramaekers, W. Dehaen, L. Adamowicz, and G. Maes, Combined Matrix-Isolation FT-IR and Theoretical Study of the Intrinsic Tautomeric, Vibrational, and H-Bonding Properties of N4-Methoxycytosine, J. Phys. Chem. A, 107, 1710 (2003).

• K. Schone, J. Smets, R. Ramaekers, L. Houben, L. Adamowicz, and G. Maes, Correlations between Experimental Matrix-Isolation FT-IR and DFT (B3LYP) Calculated Data for Isolated 1:1 H-Bonded Complexes of Water and Pyridine or Imidazole Derivatives, J. Mol. Struc., 649, 61 (2003).

• Z. Slanina, L. Stobinski, P. Tomasik, H.M. Lin, and L. Adamowicz, Quantum-Chemical Model Evaluations of Thermodynamics and Kinetics of Oxygen Atom Additions to Narrow Nanotubes, J. Nanosci. Nanotech., 3, 193 (2003).

• A.F. Jalbout, C.S. Hall, and L. Adamowicz, Isomerism of the Anion of the Indole-Water Dimer. Ab initio Study, J. Chem. Phys., 118, 10541 (2003).

• M. Cafiero, S. Bubin, and L. Adamowicz, Non-Born-Oppenheimer Calculations of atoms and molecules, Phys. Chem. Chem. Phys., invited review, 5, 1491 (2003).

• M. Cafiero, L. Adamowicz, M. Duran, and J.M. Luis, Nonadiabatic and Born-Oppenheimer Calculations of the Polarizabilites of LiH and LiD, J. Mol. Struct. (THEOCHEM), 633, 113 (2003).

• S. Bubin and L. Adamowicz, Non-Born-Oppenheimer Calculations of Excited States with Zero Total Angular Momentum (Vibrational Spectrum) of H₂, J. Chem. Phys., 118, 3079 (2003).

• M. Cafiero and L. Adamowicz, Non-Born-Oppenheimer Isotope Effects on the Polarizabilities of H₂, Phys. Rev. Lett., 89, 073001 (2002).

• M. Cafiero and L. Adamowicz, Non-Adiabatic Calculations of the Polarizability of LiH in a Basis of Explicitly Correlated Gaussian Functions, J. Chem. Phys, 116, 5557 (2002).

• M. Cafiero and L. Adamowicz, Non-Adiabatic Calculations of the Dipole Moments of LiH and LiD, Phys. Rev. Lett., 88, 33002 (2002).