Infrared Laser Stark Spectroscopy of Methyl Fluoride in He Nanodroplets.

We measured the rotationally resolved infrared spectra of helium solvated methyl fluoride at 3 μm and 10 μm, wherein lies C-H and C-F stretching bands, respectively. The linewidths (FWHM) were found to increase with increasing vibrational energy and range from 0.002 cm in the v band (C-F stretch) at ~1047 cm, to 0.

Laser Spectroscopy of Helium Solvated Clusters of Methanol and Methanol-Water in the Symmetric Methyl Stretching Band.

Mid-infrared spectra of methanol and methanol-water clusters have been investigated in the symmetric CD stretching band of CDOH and CDOD. We find that the position of this band provides a useful signature of the general type of hydrogen-bonded cluster it is associated with. Our results are consistent with those previously reported in the OH stretching region (Sulaiman, M.

Characterization of the Coriolis Coupled Far-Infrared Bands of -Vinyl Alcohol.

Rotational emission from vibrationally excited molecules are responsible for a large fraction of lines in the spectra of interstellar molecular clouds. Vinyl alcohol (VA) has two rotamers that differ in energy by 6.4 kJ/mol, both of which have been observed toward the molecular cloud, Sagittarius B2(N) [Turner and Apponi, 2001, 561, 207].

Laser spectroscopy of helium solvated molecules: probing the inertial response.

Helium is the only solvent within which molecules can "freely" rotate, albeit with an increased moment of inertia relative to the gas phase. Evidence for this can be obtained by performing infrared laser spectroscopy on molecules embedded large helium clusters (nanodroplets), which often reveals rotationally resolved lines that are more closely spaced than . The additional rotational inertia results from coupling of the helium to the molecule (rotor), and decreases in going from heavy (, SF) to light (, CH) rotors due to a partial breakdown in the adiabatic (following) approximation; faster (lighter) rotors cannot couple as well to helium since their effective interaction with helium is less anisotropic.

Observation of the elusive "oxygen-in" OCS dimer.

The carbonyl sulfide (OCS) dimer serves as a prototype system for studying intermolecular forces between nonsymmetrical linear polyatomic molecules. Here, we performed a laser spectroscopic investigation of OCS dimers embedded in helium nanodroplets and found rovibrational bands corresponding to the non-polar "sulfur-in" and parallel polar dimers that have been extensively characterized in the gas phase, as well as a new non-polar "oxygen-in" dimer that has long been predicted by theory. Frequency alternations in the rotational branches along with the absence of a Stark effect provided important clues as to its assignment.