TY - JOUR
T1 - Velocity modulation spectroscopy of molecular ions II
T2 - The millimeter/submillimeter-wave spectrum of TiF+ (X3Φr)
AU - Halfen, D. T.
AU - Ziurys, L. M.
N1 - Funding Information:
This research is supported by NSF Grant CHE-0411551 and NASA Grant NNX06AB64G. D.T.H. is supported by an NSF Astronomy and Astrophysics Postdoctoral Fellowship under Award AST-0602282.
PY - 2006/11
Y1 - 2006/11
N2 - The pure rotational spectrum of the molecular ion TiF+ in its 3Φr ground state has been measured in the range 327-542 GHz using millimeter-wave direct absorption techniques combined with velocity modulation spectroscopy. TiF+ was made in an AC discharge from a mixture of TiCl4, F2 in He, and argon. Ten transitions of this ion were recorded. In every transition, fluorine hyperfine interactions, as well as the fine structure splittings, were resolved. The fine structure pattern was found to be regular with almost equal spacing in frequency between the three spin components, in contrast to TiCl+, which is perturbed in the ground state. The data were fit with a case (a) Hamiltonian and rotational, fine structure, and hyperfine constants were determined. The bond length established for TiF+, r0 = 1.7775 Å, was found to be shorter than that of TiF, r0 = 1.8342 Å-also established from mm-wave data. The hyperfine parameters determined are consistent with a δ1π1 electron configuration with the electrons primarily located on the titanium nucleus. The nuclear spin-orbit constant a indicates that the unpaired electrons are closer to the fluorine nucleus in TiF+ relative to TiF, as expected with the decrease in bond length for the ion. The shorter bond distance is thought to arise from increased charge on the titanium nucleus as a result of a Ti2+F- configuration. A similar decrease in bond length was found for TiCl+ relative to TiCl.
AB - The pure rotational spectrum of the molecular ion TiF+ in its 3Φr ground state has been measured in the range 327-542 GHz using millimeter-wave direct absorption techniques combined with velocity modulation spectroscopy. TiF+ was made in an AC discharge from a mixture of TiCl4, F2 in He, and argon. Ten transitions of this ion were recorded. In every transition, fluorine hyperfine interactions, as well as the fine structure splittings, were resolved. The fine structure pattern was found to be regular with almost equal spacing in frequency between the three spin components, in contrast to TiCl+, which is perturbed in the ground state. The data were fit with a case (a) Hamiltonian and rotational, fine structure, and hyperfine constants were determined. The bond length established for TiF+, r0 = 1.7775 Å, was found to be shorter than that of TiF, r0 = 1.8342 Å-also established from mm-wave data. The hyperfine parameters determined are consistent with a δ1π1 electron configuration with the electrons primarily located on the titanium nucleus. The nuclear spin-orbit constant a indicates that the unpaired electrons are closer to the fluorine nucleus in TiF+ relative to TiF, as expected with the decrease in bond length for the ion. The shorter bond distance is thought to arise from increased charge on the titanium nucleus as a result of a Ti2+F- configuration. A similar decrease in bond length was found for TiCl+ relative to TiCl.
KW - Millimeter/submm spectroscopy
KW - Molecular ions
KW - Rotational
KW - Velocity modulation
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U2 - 10.1016/j.jms.2006.08.008
DO - 10.1016/j.jms.2006.08.008
M3 - Article
AN - SCOPUS:33750988754
VL - 240
SP - 58
EP - 63
JO - Journal of Molecular Spectroscopy
JF - Journal of Molecular Spectroscopy
SN - 0022-2852
IS - 1
ER -