Infrared bands of the C_2 Phillips system

Abstract

The spectrum of the C2 Phillips System (A1Πu → X1∑g+) was observed in the spectral region 3300–6500 cm−1 by using a high-resolution Fourier-transform spectrometer and a hollow-cathode discharge source. Three new bands were observed, the (2–3), (1–3), and (2–4) bands belonging to the Δυ = −1 and Δυ = −2 sequences. In addition, new lines were observed in the (0–2) band. These lines, combined with previous high-resolution data, are used in a linear least-squares algorithm to calculate Dunham coefficients with a standard deviation of 0.018 cm−1. These coefficients facilitate the accurate prediction of wave numbers for the vibrational levels with υ″ and υ″.between 0 and 4.