Electronic absorption spectrum of the NCS free radical

Abstract

Absorption bands of NCS between 3300 Å and 4000 Å have been assigned to two electronic band systems, A(2Πi) – X(2Πi) with its origin at 26 054 cm−1, and B(2Σ+) – X(2Πi) with its origin at 26 844 cm−1. Rotational analyses have been carried out for the stronger bands, yielding rotational constants B0 = 0.2036 cm−1 (A state), B0 = 0.1906 cm−1 (A state), and B0 = 0.1969 cm−1 (B state). In addition to vibronic interactions within the two 2Πi states (Renner effect) there is considerable evidence for vibronic interaction between the A(2Πi) and B(2Σ+) states.