His area of research is applications-oriented theoretical quantum chemistry, which includes ab initio molecular orbital and density functional calculations of ground and excited potential energy surfaces (PES) for polyatomic molecules, radicals, and clusters with applications to combustion, atmospheric and interstellar chemistry, vibrational and electronic spectroscopy, and optical properties of nano-size materials. The calculations represent a valuable tool for prediction of various physico-chemical properties of molecules and radicals, reaction mechanisms, rate constants and product branching ratios, and for interpretation of experimental data.