AMMONIA DIMER - MEASUREMENT OF THE HYPERFINE STRUCTURE AND THE DIPOLE MOMENT OF THE G AND E STATE
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Date
1993
Journal Title
Journal ISSN
Volume Title
Publisher
Ohio State University
Abstract
When the ammonia dimer, $(NH3)2$, had been measured in the microwave region1 for the first time, only the G states (group G\%), $k=0$, were observed. All lines showed a rather complex 14N quadrupole hyperfine structure. Combined with dipole moment measurements Klemperer et al. proposed the ``cyclic structure'' which was in disagreement to former ab initio theories predicting the hydrogen bonded structure. New $measurements^{2,3}$ demonstrated, that $(NH_{3})$, exhibits large amplitude motions. A structural determination in other tunneling states is therefore of special interest. Dipole moment measurements carried out at the tunable FIR spectrometer in Nijmegen gave for the $G(G\frac{1}{2}) k=1$ state a surprisingly small dipole moment. Using the pulsed Molecular beam microwave Fourier transform spectrometer in Kiel the hyperline structure in the $J=2-1\,E_{3}/E_{4}(G\frac{1}{3},G^{1}_{4})$ states could be fully resolved. These measurements should help in understanding the structure of ($NH_{3})_{2}$.
Description
$^{1}$ G. T. Fraser, D. D. Nelson, A. Charo, and W. Klemperer, J. Chem. Phys. 82, 2535 (1985). 2 M. Havenith, E. Linnartz, E. Zwart, A. Kips, J. J. ter Meulen, and W. L. Meerts, Chem. Phys. Lett. 193, 261 (1992). 3 J. G. Loeser, C. A. Schmuttenmaer, R. C. Cohen, M. J. Elrod, D. W. Steyert, and R. J. Saykally, and R. E. Bumgarner and G. A. Blake, J. Chem. Phys. 97, 4727 (1992).
Author Institution: Institut f\""{u}r Physikalische Chemie, Universit\""{a}t Kiel; Institut f\""{u}r Physikalische Chemie, Institut f\""{u}r Angewandte Physik; Molecular and Laser Physics, University of Nijmegen
Author Institution: Institut f\""{u}r Physikalische Chemie, Universit\""{a}t Kiel; Institut f\""{u}r Physikalische Chemie, Institut f\""{u}r Angewandte Physik; Molecular and Laser Physics, University of Nijmegen