Adamowicz Group HomePage Publications Curriculum Vitae Send eMail Telephone: (520) 621-6607 FAX: (520) 621-8407 ludwik@U.Arizona.EDU

My research has been focused on the development and application of quantum chemical theoretical methods for more accurate determination of the stationary and dynamic quantum states of molecular systems. The methodological development has comprised theory formulation, computational implementation of theory and application calculations. The considerable recent progress in the computational capabilities of both hardware and software opens a unique opportunity to employ new theoretical techniques to larger polyatomic molecules, leading to more reliable predictions of their properties and structures. Development of new theoretical techniques in my group has evolved around the following topics:

- 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.

- 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.

The development of methodologies will be closely correlated with my interests, in particular chemical phenomena, which include: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.

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.

Selected Publications

J. Smets, A. Destexhe, L. Adamowicz and G. Maes, Matrix-Isolation FT-IR Studies and Ab-Initio Calculations of Hydrogen-Bonded Complexes Modeling Cytosine or Isocytosine Tautomers. 4. H-bonded Complexes of 1 - CH₃ - 2 - Pyrimidone and N,N,1 - tri - CH₃- Cytosine with Water, J. Phys. Chem., accepted for publication.

D.B. Kinghorn and L. Adamowicz, A New N-Body Potential and Bases Functions for Vibrational Energy Calculations, J. Chem. Phys. 106, 8760 (1997).

D.B. Kinghorn and L. Adamowicz, The Electron Affinity of Hydrogen, Deuterium and Tritium: A Non-Adiabatic Variational Calculation Using Explicitly-Correlated Gaussian Bases Functions, J. Chem. Phys. 106, 4589 (1997).

M. Van Bael, K. Schoone, L. Houben, J. Smets, W. McCarthy, L. Adamowicz, M. Nowak and G. Maes, Matrix-Isolation FT-IR studies and Theoretical Calculations of Hydrogen-bonded Complexes of Imidazole. Comparison Between Experimental Data and Different Theoretical Methods, J. Phys. Chem. 101, 2397 (1997).

L. Adamowicz and J.-P. Malrieu, Multi-Reference Self-Consistent Size-Extensive State-Selective Configuration Interaction, J. Chem. Phys. 105, 9240 (1996).

J. Smets, W.J. McCarthy and L. Adamowicz, Dipole-Bound Electron Attachment of Uracil-Water complex. Theoretical Ab-Initio Study, J. Phys. Chem. 100, 14655 (1996).

Chemistry Faculty

Maintained by ChemInfo

Department of Chemistry Homepage