||Over the past few decades nanoscience and molecular biology has shown a strong growth worldwide in many areas of research and proved their significance in todays ́ competitive environment. However, there still remains an enormous potential for further development which could revolutionize every area of human life. Unfortunately, in some cases, that potential is screened out by complexity and multilevel character of systems and processes at a nanometer scale. The success of future applications in a high-tech industry requires deep understanding of fundamental mechanisms on different levels of description and their communication. That could be provided only by appropriate combination of experimental study with predictive theoretical modeling. Nowadays, more and more scientists in different fields of chemistry and biology are using computational modeling methods in their research, either as a technique per se, or as a complement to experimental work. However, despite the in- creasing attention to computational nanoscience and biology the specificity of application of standard theoretical and computational modeling in nanotechnology and bioscience is complicated due to complexity of the systems of interest and needs to be discussed separately, especially in the view of multilevel representation of systems and pro- cesses on nanoscale. One of most important and demanding applications in computational chemistry is multiscale modeling of properties and interaction of macro/bio molecules in solvents and mixtures. The presentation will address different aspects of theoretical and computational approaches and their combination at the different time and length scales to model impact of solvents on physicochemical properties of molecules as geometry, conforma- tional equilibria, reaction rates, as well as their UV-vis, IR, or NMR spectra. It will focus on the combination of statistical-mechanical molecular theory of liquids (3D reference interaction site model, known as 3D-RISM) with density functional theory (DFT) which provides the accurate and efficient way to predict the electronic properties of molecular system in different solvents and mixtures with high level of accuracy comparable with simulations but with less computational cost . Similar to explicit solvent simulations, 3D-RISM properly accounts for chemical and physical activity of both solute and solvent molecules, such as hydrogen bonding and hydrophobic forces, by yielding the 3D site density distributions of the solvent. Moreover, it readily provides, via analytical expressions, the solvation thermodynamics, including the solvation free energy, its energetic and entropic decomposition, and partial molar volume and compressibility. Recently the number of new approaches and approximations was de- veloped in order to increase efficiency of 3D-RISM and DFT combination. They could be subdivided into two main groups focused on the optimization of 3D-RISM algorithm (memory optimization, parallelization, etc.) and methodology improvements . I will present a review and analysis of latest achievements focused on improves of accuracy and applicability the combination. Some examples will be also discussed.
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 Gusarov S., Bhalchandra P., Kovalenko A., Efficient treatment of solvation shells in 3D molecular theory of solvation, , J. Comp. Chem, 33, 1, pp. 1478-1494 (2012).