A STUDY OF THE ELECTRONIC STRUCTURE AND PROPERTIES OF THE PROPARGYL RADICAL
By means of B3LYP/6-311++G(<i>3df,3pd</i>) the electron density distribution in the propargyl radical CH<sub>2</sub>CCH is obtained. Within the Quantum Theory of Atoms in Molecules the phenomenon of conjugation and the spin density distribution of the unpaired electron in CH<sub>2</sub>CCH are studied at the qualitative level. Characteristics of the electronic structure of CH<sub>2</sub>CCH and its parent molecules CH<sub>3</sub>-C≡CH and CH<sub>2</sub>=C=CH<sub>2</sub> are compared. With the use of the rigid rotator-anharmonic oscillator model the thermodynamic properties of the propargyl radical and enthalpies of bond cleavage in propyne and allene are calculated in the temperature range 298-1500 K. The relationship between the electronic and thermodynamic properties of CH<sub>2</sub>CCH is considered and its conjugation energy is calculated.