We report a preliminary ab initio study of the ground state of the HCCS radical. The results are discussed in relation to a tiansient absorption spectrum observed in the flash photolysis of thiophene.
Theoretical studies of the new radicals SiNNH and SiCOH
โ Scribed by Kangnian Fan; Suehiro Iwata
- Publisher
- Elsevier Science
- Year
- 1992
- Tongue
- English
- Weight
- 608 KB
- Volume
- 195
- Category
- Article
- ISSN
- 0009-2614
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โฆ Synopsis
Geometry optimization and harmonic vibrational analysis were carried out for new radicals, SiNNH and SiCOH, as well as their isomers, HSiNN and HSiCO, at several levels of ab initio SCF calculations (ROHF, UHF and MCSCF) with the 6-3 1G' basis set. To examine the effects of electron correlation on the equilibrium geometry, the bond lengths rSiN and rNN of the isomer SiNNH were optimized with CI calculations. Each of these four molecules has been found to be slightly asymmetric with a *A" ground state. The predicted rotational constants suggest that the isomer SiNNH is one of the best candidates for the free radical detected in the envelope of the carbon star IRC+ 102 16, and none of the other three species, HSiNN, SiCOH and HSiCO, can be that one. From the calculated results. the nature of the chemical bonds in these molecules has been discussed in detail.
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