Ab initio investigation of high multiplicity Σ⁺"⁻"Σ⁺ optical transitions in the spectra of CN and isoelectronic species
- Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
Due to high-level ab initio calculations, we predict the existence of a strong 4Σ⁺"⁻"Σ⁺ optical transition (dav=1.6 D) near 328 nm (T00 = 30 460 cm–1), analogous to the B2Σ⁺"⁻"X2Σ⁺ violet system, (dav=1.7 D) in the near-ultraviolet spectrum of CN. The lower state of the predicted transition is the lowest-lying state of quartet multiplicity and has been observed previously through its perturbations of the B state. The predicted transition will enable determination of the equilibrium properties of the metastable lowest quartet state of CN. The lowest energy metastable sextet state of CN is also calculated to be quasibound (re=1.76 Å, ωe = 365 cm–1) , and a 6Σ⁺"⁻"6Σ⁺ transition, analogous to those for the doublet and quartet multiplicities, is predicted (dav=2.2 D). Investigation of the isoelectronic BO, C$$^{–}_{2}$$, and N$$^{+}_{2}$$ molecules reveals that differences in 2s22px and 2s12px+1 atomic energies play the key role in determining the magnitude of the 5σ(2p)←4σ(2s)-derived Σ⁺"⁻"Σ⁺ transition energies for the different multiplets. Furthermore, the strong stabilization of 2s22px character with respect to 2s12px+1 in BO and N$$^{+}_{2}$$ leads to strongly bound lowest 6Σ⁺ states with binding energies as high as 2.0 eV. We think that these newly predicted sextet states could be identified through their perturbations of quartet states of the relevant molecules.
- Research Organization:
- Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Grant/Contract Number:
- FG02-87ER13671
- OSTI ID:
- 1557817
- Journal Information:
- Journal of Molecular Spectroscopy, Vol. 258, Issue 1-2; ISSN 0022-2852
- Publisher:
- ElsevierCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Photodissociation and photoionisation of atoms and molecules of astrophysical interest
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journal | June 2017 |
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