Abstract
The aim of this work is to conduct experimental studies and quantum-chemical calculations by the method of functional of the energy density of DFT B3LYP/6-31G*, to study the structure and thermodynamic properties of alkyl- and alkenyladamantanes C11-C14 and a comparison of the calculated and experimental characteristics of homologues. It is possible to calculate energies of excited states in DFT. The good quality of the results and the low cost made DFT the main computational tool in quantum chemistry. For each molecule the geometrical arrangement of the atoms has been optimised using analytical calculation methods. By calculating the frequencies of normal vibrations using second derivatives, it was confirmed that the stationarity points determined by geometry optimization are energy minima. Since obtaining experimental data on the relative thermodynamic stability of isomers of alkyl- and alkenyladamantanes is fraught with certain difficulties, including those in the identification of the isomers and determination of their spatial structure, computational methods are anticipated to play a very important role in solving these problems.