LIF Measurements on the C 2 Σ + – X 2 II r Transitions of the CD Radical

Abstract

Laser-induced fluorescence (LIF) measurements are made on the C²Σ⁺- X²II _r (λ = 314 nm) transition of CD, which is produced by a microwave-excited Ar/CD₄ process plasma. The experiment is realized by using a frequency-doubled cw ring dye laser as the tunable light source. Due to the small bandwidth (≈3 MHz) of the exciting UV laser, the exact line positions of spin-doubled rotational lines in the P-branch (N” = 2 to 5 and N” = 8 to 13) of the first vibrational band (v’ = v” = 0) could be determined. The resolution is limited only by Doppler broadening, which amounts in our plasma (T = 450 K) to about 4 GHz. With these new values of line positions, a modified spin-splitting constant of γ = 0.051 ± 0.006 cm⁻¹ is calculated.