A Dramatic Spin–Orbit Effect Observed in the Vibrational Frequencies of the Chloroiodomethane Cation

Abstract

The vibrational spectrum of [CH235ClI]+ (see formula) was recorded by mass-analyzed threshold ionization (MATI) spectrometry. Spin–orbit effects were used in density functional calculations to determine the structure of the ground state of the cation. The results suggest that spin–orbit terms should be treated the same as other relativistic effects in some cases.