Molecular opacities of low-lying states of oxygen molecule*

Abstract

The X 3 Σ g − , A′3Δu, A 3 Σ u + , 13Πg, and B 3 Σ u − electronic states of oxygen molecule (O2) are calculated by the multi-configuration self-consisted filed (MRCI) + Q method with the scalar relativistic correction and core–valence correlation correction. The obtained spectroscopic constants of the low-lying bound states are in excellent agreement with measurements. Based on the accurately calculated structure parameters, the opacities of the oxygen molecule at the temperatures of 1000 K, 2000 K, 2500 K, and 5000 K under a pressure of 100 atm (1 atm = 1.01325 × 105 Pa) and the partition functions between 10 K and 104 K are obtained. It is found that with the increase of temperature, the opacities for transitions in a long wavelength range are enlarged because of the larger population on excited electronic states at the higher temperatures.

A Theoretical Study of Temperature-dependent Photodissociation Cross Sections and Rates for O2

“…Dipole-allowed TDMs between the abovementioned six electronic states are shown in Figure 2 Stransition shows the same trend as those computed by Allison et al (1986) and Liang et al (2020) for R larger than 1.24 Å. For R smaller than about 1.24 Å, our TDM exhibits a similar trend to that given by Allison et al (1986), but different from that presented by Liang et al (2020).…”

Spectroscopy and molecule opacity investigation on excited states of SiS

“…Furthermore, previous work has also indicated that the origin of opacity and the absorption spectrum in astrophysical phenomena predominantly lies within molecular entities. [38,39] In order to illuminate the effect of surrounding temperature on molecular opacities, the molecular opacities originating from the X 1 Σ + , 1 1 Π and 2 1 Σ + states of SiS at different surrounding temperatures (300 K, 1000 K, 3000 K and 4500 K) are plotted in Figs. 6(a)-6(d).…”

Molecule opacity study on low-lying states of CS

“…The opacities of molecules in atmospheric and astrophysical circumstances have been investigated in previous work by using the theoretical method mentioned in Section 2. [43][44][45][46] By utilizing the calculated vibration-rotation levels, wavefunctions, DMs and TDMs, the molecular opacity and partition function of CS are computed. The partition function is very important input parameters in spectral analysis and radiative transfer simulation in atmospheric and astrophysical fields.…”