The Structure of Water Dimer from Molecular Beam Electric Resonance Spectroscopy.
Abstract
Molecular beams of hydrogen bonded water dimer, generated in a supersonic nozzle, have been studied using electric resonance spectroscopy. Radio frequency and microwave transitions have been observed in (H2(16)O)2, (D2(16)O)2, and (H2(18)O)2. Transitions arising from both pure rotation and rotation-tunneling occur. The pure rotational transitions have been fit to a rigid rotor model to obtain structural information. Information on the relative orientation of the two monomer units is also contained in the electric dipole moment component along the A inertial axis, which is obtained from Stark effect measurements. The resultant structure is that of 'translinear' complex with an oxygen-oxygen distance, R(00), of 2.98(1) A, the proton accepting water axis is 58 (6) degrees with respect to R(00), and the proton doning water axis at -51 (6) degrees with respect to R(00). This structure is consistent with a linear hydrogen bond and the proton acceptor tetrahedrally oriented to the hydrogen bond. The limits of uncertainty are wholly model dependent and are believed to cover variations from the zero-point vibrational structure observed to the equilibrium structure. The A component of the electric dipole moment shows strong dependence on J and K and is about 2.6D. Centrifugal distortion constants have been interpreted in terms of the monomer-monomer stretching frequency and give omega = 150/cm. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1976
- Accession Number
- ADA041913
Entities
People
- John S. Muenter
- Kenneth M. Mack
- Thomas R. Dyke
Organizations
- University of Rochester