New Infrared Spectra of Acetylene-Water Dimers: First Determination of the Rotational Constant and Another -Dependent Anomaly.

Infrared spectra of acetylene-water complexes are studied in the regions of the HO ν bend (1600 cm) and the DO ν/ν stretches (2670-2808 cm), using tunable infrared sources to probe a pulsed supersonic slit jet expansion. In the HO bend region, there is a puzzling absence of = 0 transitions for CH-HO, while both = 0 and 1 are observed for CD-HO. This continues a pattern of "missing" states noted in previous infrared studies of acetylene-water.

Water-carbon disulfide dimers: observation of a new isomer and structure theory.

The weakly bound dimer water-carbon disulfide is studied by structure theory and high-resolution infrared spectroscopy. The calculations yield three stable minima in the potential energy surface, all planar. The most stable, isomer 1, was observed previously by microwave spectroscopy.

Infrared spectra of partially deuterated water dimers in the fundamental O-D stretch region.

Spectra of mixed H/D water dimers are studied in the mid-infrared region of the O-D stretch fundamental (2630-2800 cm-1) using a pulsed supersonic slit jet and a tunable optical parametric oscillator infrared source. Over 30 bands, belonging to nine of the ten possible isotopologues (only H2O-HOD is missed), are observed and analyzed. The implications for excited state tunneling splittings, lifetime effects, and vibrational shifts are discussed.

Spectra of the D2O dimer in the O-D fundamental stretch region: The acceptor symmetric stretch fundamental and new combination bands.

The O-D stretch fundamental region of the deuterated water dimer, (D2O)2, is further studied using a pulsed supersonic slit jet and a tunable optical parametric oscillator infrared source. The previously unobserved acceptor symmetric O-D stretch fundamental vibration is detected, with Ka = 0 ← 0 and 1 ← 0 sub-bands at about 2669 and 2674 cm-1, respectively. The analysis indicates that the various water dimer tunneling splittings generally decrease in the excited vibrational state, similar to the three other previously observed O-D stretch fundamentals.

Understanding the high-resolution spectral signature of the N2-H2O van der Waals complex in the 2OH stretch region.

We present the observation of the N2-H2O van der Waals complex in the 2OH stretch overtone region. The high-resolution jet cooled spectra were measured using a sensitive continuous wave cavity ringdown spectrometer. Several bands were observed and vibrationally assigned in terms of ν1, ν2, and ν3, the vibrational quantum numbers of the isolated H2O molecule, as (ν1'ν2'ν3')←(ν1″ν2″ν3″)=(200)←(000) and (101) ← (000).