39466-31-4Relevant academic research and scientific papers
An investigation of the hydrogen-bonded dimer H3NHBr by pulsed-nozzle, Fourier-transform microwave spectroscopy of ammonium bromide vapor
Howard, N. W.,Legon, A. C.
, p. 6722 - 6730 (1987)
The ground-state rotational spectrum of a dimer of ammonia and hydrogen bromide has been detected by using the technique of Fourier-transform microwave spectroscopy in a Fabry- Perot cavity to examine a supersonically expanded gas pulse composed of ammonium bromide vapor entrained in argon.The spectroscopic constants B0o, DJ, DJK, Ξ(14N), Ξ(79Br), and Ξ ( 81Br ) have been determined ( where appropriate ) for the four symmetric-top type isotopic species (14NH3, H79Br), (14NH3, H81Br), (15NH3, H79Br), and (15NH3, H81Br) and for the first of these the values are as follows: B0 = 3226.862 ( 1 ) MHz, DJ = 9.0 ( 2 ) kHz, DJK =142.2(6) kHz, Ξ(14N) = - 3.183(8) MHz, and Ξ(79Br) = 361.245(6) MHz.The spectroscopic constants have been interpreted in terms of a hydrogen-bonded dimer of C3v symmetry, having r(NBr) = 3.255 Angstroem and the hydrogen-bond stretching force constant k0 =13.4 N m -1.A detailed analysis has demonstrated that Ξ (79Br ) is consistent with a model of the dimer in which only a small electrical rearrangement in the HBr subunit occurs on dimer formation ( as opposed to proton transfer to NH3 ) and that this can be viewed as the transfer of ca.O.1e from H into the 4pz orbital of Br.
