- Anomalous solvation of small amines, regarded as a formidable solvability problem, was explained. Previous molecular modeling efforts of several renowned experts had failed because of inadequate treatment of internal rotations. - An explanation was found for the strong rotational enhancements of hydrogen transfer reactions observed by a number of authors. The mechanism found should also be the basis of strong microwave acceleration of chemical reactions reported in many papers. The application of this method is rapidly increasing but the progress has been hampared by the lack of knowledge about the mechanism. - A model of ozone formation mechanism was derived which is well in agreement with surprising isotope effect recently found experimentally. - It was shown that, contrary to what was generally accepted, the values of the Swain-Schaad exponent biger than 3.3 do not necessarily mean that hydrogen tunneling is involved in hydrogen transfer process. The possibility of an alternative mechanism was then purposed for the hydrogen transfer observed in several enzymatic reactions and so far ascribed to tunneling. - Chemical shift isotope effect was studied in a small intramolecular hydrogen bonded system picolinic acid N-oxide. We also considered the effects of polar environment on the chemical shifts. We solved variationally vibrational Schroedinger equation for OO and OH vibrations, and the effects of solvation were included on the solvent reaction field level. - Using classical molecular dynamics simulation we studied proton dynamics in a hydrogen bonded system immersed in polar solvent. The application of classical MD is justified by low barrier hydrogen bond. - We studied chemical reactivity associated with two estrogen ultimate carcinogens in the process of Gua alkylation. Linear free energy relationship was used. We conclude that some other step is responsible for the difference in carcinogenicity between estron and estradiol ulltimate carconogens.