Many-body Effects In Hydrogen-bonded Complexes Containing Watson-Crick Base Pair Or N-methylacetamide Dimer And Water Molecules

The quantitative evaluation of the strength of many body effects for complexes containing biomolecules and water molecules is very important because many body effects are ubiquitous and play important roles in biosystems.In this thesis,the many body effects in hydrogrn-bonded complexes containing Watson-crick base pair or N-methylacetamide dimmer and water molecules are investigated based on the calculation results at the M06-2X/6-31+G(d,p)level.It is found that the total interaction energies can be estimated by adding the 2-body interaction energies and 3-body interaction energies together.It is also found that the 2-body and 3-body interactions energies depend strongly on the intermolecular distances and those in which the summation of the intermolecular distances is beyond a certain distance can be ignored.