Study Of The Spectra Of D~3△-a~3Ⅱ(5,0) Of CO Molecular

CO has been found abundant in interstellar space. It plays an important role in the process of chemical reaction, the field of plasma, the biomedicine and environment. It is significant to study its spectra. The triplet band system of CO is complicated. The perturbation between molecular states adds difficulty to the assignment and identification of spectral lines through changing their positions and intensities. It is very necessary to carry out the theoretical work.This paper studied the triplet band d³â–³-a³âˆ(5, 0) theoretically, taking the perturbation of A¹âˆ(v=1) with d³â–³₁(v=5)into account. The results are as follows:(1) The high sensitive d³â–³-a³âˆ(5, 0) band experimental data involved d³â–³₂ and d³â–³₃ components are reanalyzed using effective Hamiltonian method. The result shown that the perturbation of A¹âˆ(v=1) can be neglected. Further the energy shifts and spectral intensity changes of d³â–³₁, d³â–³2 and d³â–³₃ due to A¹âˆ(v=1) perturbation are calculated theoretically. It is found that the energy shift forâ–³₁ is significant and it is up to 4 cm^-1 for J=1. It decreases with increasing/. The energy shifts are very small with small J values forâ–³₂ andâ–³₃.(2) The intensities of spectral lines of d³â–³-a³âˆ(5, 0) band are qualitatively analyzed according to the change in wavefunction caused by the perturbation of A¹âˆ(v=1) with d³â–³₁(v=5). The result shows that the spectral intensity of d³â–³₁-a³âˆchanges smaller up to 20%.This change decreases with increasing J values. The changes relative to d³â–³₂ and d³â–³₃, are small enough to be neglected.(3) The relative intensities of different branches within the same vibrational band are decided by HL factors. The HL factors of 27 branches of d³â–³-a³âˆ(5, 0) band have been calculated. The effects of molecular state mixing and perturbation of A¹âˆ(v=1) with d³â–³₁(v=5)are discussed. The result shows that the relative intensities of ³â–³₃-³âˆ₀ ³â–³₃-³âˆ₁ and ³â–³₂-³âˆ₀ are very small. They are contributed by the molecular state mixing. The perturbation lead to the larger decrease of ³â–³₁-³âˆ₀,â–³₁-³âˆ₁ and ³â–³₁-³âˆ₂ and has almost no effect on other branches. This result is in agreement with that of part (2).