Terahertz vibration-rotation-tunneling spectroscopy of the ammonia dimer: characterization of an out of plane vibration.

Terahertz vibration-rotation-tunneling spectroscopy of the ammonia dimer. II. A-E states of an out-of-plane vibration and an in-plane vibration.

Terahertz vibration-rotation-tunneling transitions have been measured between ca. 78.5 and 91.9 cm-1, and assigned to A-E (ortho-para) combinations of NH3 monomer states. The spectrum is complicated by inversion splittings that correlate to E symmetry monomer rovibronic states. Twenty progressions have been assigned to six excited states involving an out-of-plane vibration and an in-plane inter...

Measurement of the intermolecular vibration-rotation tunneling spectrum of the ammonia dimer by tunable far infrared laser spectroscopy

Over 150 lines in six tunneling subbands of an intermolecular vibration located near 25 cm r have been measured with partial hyperflne resolution and assigned to (NH, )2. The transitions sample all three types of tunneling states (A, G, E) and are consistent with the following assumptions: ( 1) G,, is the appropriate molecular symmetry group; (2) the equilibrium structure contains a plane of sy...

Terahertz vibration–rotation–tunneling spectroscopy of water clusters in the translational band region of liquid water

We report the first direct observation of the hydrogen-bond stretching vibration for a water cluster. A perpendicular band of ~D2O!3 was measured by terahertz laser vibration–rotation–tunneling spectroscopy at 142.8 cm in the ‘‘translational band’’ region of the liquid corresponding to the hindered translational motions of water molecules. We have tentatively assigned the spectrum to transition...

Far-infrared VRT spectroscopy of the water dimer: Characterization of the 20 μm out-of-plane librational vibration.

We report the first high-resolution spectra for the out-of-plane librational vibration in the water dimer. Three vibrational subbands comprising a total of 188 transitions have been measured by diode laser spectroscopy near 500 cm(-1) and assigned to (H2O)2 libration-rotation-tunneling eigenstates. The band origin for the Ka = 1 subband is ~524 cm(-1). Librational excitation increases the inter...

Stark effect and dipole moments of the ammonia dimer in different vibration-rotation-tunneling states