15min:

PAUL L. RASTON, CHRISTOPHER P. MORADI, Department of Chemistry, University of Georgia, Athens, Georgia 30602-2556; JAY AGARWAL, JUSTIN. M. TURNEY, HENRY F. SCHAEFER III, Center for Computational Chemistry, University of Georgia, Athens, Georgia 30602-2556; GARY E. DOUBERLY, Department of Chemistry, University of Georgia, Athens, Georgia 30602-2556.

The ethyl radical has been isolated and spectroscopically characterized in ⁴He nanodroplets. The five fundamental CH stretch bands are observed near 3 µm and have band origins shifted < 1 cm^-1 from those reported for the gas phase species.^, The symmetric CH₂ stretching band ( ₁ ) is rotationally resolved, revealing nuclear spin statistical weights predicted by G₁₂ permutation-inversion group theory. A permanent electric dipole moment of 0.28 (2) D is obtained via the Stark spectrum of the ₁ band. The four other CH stretch fundamental bands are broadened in helium droplets and lack rotational fine structure. The approximately 1-2 cm^-1 line widths for these bands are attributed to the homogeneous broadening associated with solvent-mediated rovibrational relaxation dynamics. In addition to these five fundamentals, three A₁' overtone/combination bands are observed and have resolved rotational substructure. These are assigned to the 2 ₁₂ , ₄ + ₆ , and 2 ₆ bands through comparisons to anharmonic frequency computations at the CCSD(T)/cc-pVTZ level of theory.