The structure of the HCCCO radical. Rotational spectra and hyperfine structure of monosubstituted isotopomers

Autor:	J. K. G. Watson, Andrew L. Cooksy, C. A. Gottlieb, Patrick Thaddeus
Rok vydání:	1994
Předmět:	Fermi contact interaction Proton Unpaired electron Chemistry Ab initio quantum chemistry methods Carbon-13 General Physics and Astronomy Physical and Theoretical Chemistry Ground state Photochemistry Molecular physics Hyperfine structure Isotopomers
Zdroj:	Scopus-Elsevier
ISSN:	1089-7690 0021-9606
Popis:	Rotational spectra of six isotopomers of the propynonyl radical—HCCCO, DCCCO, H13CCCO, HC13CCO, HCC13CO, and HCCC18O—have been measured and analyzed, yielding the geometry and leading hyperfine constants of its 2A’ vibronic ground state. The radical is found to have an acetylenic carbon chain with the unpaired electron strongly localized on the carbon atom Cc, with the carbon atom positions labeled according to HCaCbCcO. The geometry, assumed to be fully trans, is given by the parameters θHCC = 168°, θCCC = 163°, θCCO = 136.5°, rHCa = 1.060 A, rCaCb = 1.219 A, rCbCc = 1.387 A, and rCcO = 1.192 A. The Fermi contact hyperfine constants are ac(H) = −11.593(41) MHz, ac(13Ca) = 35.8(1.4) MHz, ac(13Cb) = 166.2(3.8) MHz, and ac(13Cc) = 347.6(3.2) MHz, where dipolar terms in the proton and 13Ca hyperfine structure have been neglected. No evidence of other HCCCO isomers is found in the spectra, although ab initio calculations identify a second minimum at a cumulenic structure with the unpaired electron localized a...
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_dedup___::e81aec51a4022dd79a8e6f387200a269 https://doi.org/10.1063/1.468493 Zobrazit plný text záznamu