Theoretical studies on the structures and electronic spectra of C75B−

Intermediate neglect of differential overlap (INDO) calculations were used to study the structure of C₇₅B^?—the isoelectronic molecule of C₇₆. It was found that the boron atom mainly substitutes the second carbon atom (there are 19 types of carbon atoms in C₇₆). The electronic spectra of all the possible isomers of C₇₅B^? were calculated based on the optimized geometries. It was shown that the UV‐Vis spectra of C₇₅B^? and C₇₆ resemble each other in many ways with the exception of the absorptions beyond 700 nm. The red shift of the absorptions was rationalized and nature of transition of the peaks discussed. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2003