Calculation of CO(XΣ) + 0(P) recombination chemiluminescence spectrum

Relative emission spectra for the bent to linear, CO₂(¹B₂)---CO₂(X¹Σ⁺_g) transitions have been calculated using the model: harmonic oscillator, symmetric-top wavefunctions and energy levels for CO₂(¹B₂); first-orer Fermi resonance vibrational wavefunctions and energy levels for CO₂(X¹Σ⁺_g); a Boltzmann distribution of vibrational and rotational states in CO₂(¹B₂); and a constant electronic transition moment. With the literature CO₂(¹B₂) molecular structure, spectra calculated using this model show characteristics similar to the low-temperature chemiluminescence from the combination of atomic oxygen and carbon monoxide. The calculated spectra account for experimental band positions to wavelengths of 570 nm and the weak dependence of the spectra on temperature over the range 206–353 K. The latter result was obtained from a CO₂(¹B₂) bending fundamental of 600 cm⁻¹. The calculated spectra also show a violet-shift in intensity and an attenuated band structure at higher temperatures. The magnitude of these effects depends on the CO₂(¹B₂) force constants and not on the CO₂(¹B₂) molecular structure.