On October 23, 2025, a seminar titled “Review of Some Computational Chemistry Programs and Methods” was held at the Raphael Agladze Institute of Inorganic Chemistry and Electrochemistry. The seminar was led by Dimitri Lochoshvili, Senior Researcher at the Department of Coordination Compounds and Sorption-Catalytic Processes. The aim of the seminar was to present modern approaches in computational chemistry and discuss software tools applied for analyzing and predicting molecular structures and properties of chemical systems.

Molecular Mechanics Method

The molecular mechanics approach is based on the principles of classical mechanics and electrostatics. It treats molecular systems within the framework of classical physics, allowing visualization and analysis of three-dimensional molecular structures on a computer

Although the method is simple and efficient, its accuracy is limited, which restricts its use for studying complex molecular systems.

Quantum-Chemical Methods

To achieve higher accuracy, scientists employ various quantum-chemical methods, including:

Ab initio methods,

Semi-empirical approaches,

Density Functional Theory (DFT).

Ab initio methods provide relatively high accuracy of calculations. When performing ab initio computations, the computer spends most of its processor time calculating the integrals of electron–electron interactions. As the size of a molecule increases, the number of such integrals grows accordingly, leading to longer computation times. Therefore, ab initio methods are applicable mainly to small molecules.

Semi-empirical methods simplify calculations by replacing complex integrals with parameters derived from experimental data. These approaches enable the study of molecules containing hundreds of atoms with reasonable accuracy.

Semi-empirical methods simplify calculations by replacing complex integrals with parameters derived from experimental data. These approaches enable the study of molecules containing hundreds of atoms with reasonable accuracy.  Density Functional Theory (DFT) attract considerably greater attention because they involve a smaller number of approximations and provide high accuracy of results, comparable to that of ab initio methods. Using DFT, it is possible to perform quantum-chemical calculations for much larger molecules than with ab initio approaches.

Software Packages

During the seminar, several popular computational chemistry programs were discussed, including:

Q-Chem – one of the leading programs for ab initio and DFT calculations;

IQMol – a visualization tool designed for Q-Chem output;

ChemOffice – a multifunctional suite for molecular modeling and structural analysis.

Dimitri Lochoshvili presented a case study on para-pyridinealdehyde isonicotinoylhydrazone, where DFT calculations were performed using three different methods to compare accuracy and performance.

The seminar clearly demonstrated that modern computational chemistry methods are indispensable tools for the investigation and prediction of molecular systems.

The appropriate selection of methods and software ensures an optimal balance between computational efficiency and accuracy, which is crucial for the design of new compounds and the analysis of reaction mechanisms.