The infrared absorption intensity of a C70 molecule is calculated by a semi-empirical molecular orbital calculation library, mopac93. Geometrical optimization for C70 is obtained by the MNDO and PM3 methods. The calculated molecular vibration frequencies of C70 at the optimized geometry are shifted to higher frequency by about 15.5% compared with the experimental result. The calculated result of the infrared absorption intensity shows that there are only 17 modes which have a large intensity among the 31 infrared-active modes predicted by group theory. A comparison of the intensities of the infrared absorption spectra between theory and experiment is satisfactory.
ASJC Scopus subject areas
- Physics and Astronomy(all)
- Physical and Theoretical Chemistry