Structure determination of the nonlinear hydrocarbon chains C _9H_3 and C_(11)H_3 by deuterium labeling

摘要

A systematic deuterium labeling experiment is presented that aims at an unambiguous determination of the geometrical ground state structure of the C_9H_3 and C_(11)H_3 hydrocarbon chains. Cavity ring-down spectroscopy and special plasma expansions constituting CH, CD, and CHD are used to record optical transitions of both species and their (partially) deuterated equivalents in the 19 000 cm~-1 region. The number of observed bands, the quantitative determination of isotopic shifts, and supporting calculations show that the observed C_9H_3 and C_(11)H_3 spectra originate from HC_4(CH)C _4H and HC_4C(C_2H)C_4H species with C_(2v) symmetry. This result illustrates the potential of deuterium labeling as a useful approach to characterize the molecular structure of nonlinear hydrocarbon chains.