An investigation of the hydrogen-bonded dimer H3NHBr by pulsed-nozzle, Fourier-transform microwave spectroscopy of ammonium bromide vapor

Article abstract of DOI:10.1063/1.452371

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, D_J, D_JK, 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, D_J = 9.0 ( 2 ) kHz, D_JK =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 C_3v symmetry, having r(N<*>Br) = 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 4p_z orbital of Br.

Full text of DOI:10.1063/1.452371

An investigation of the hydrogenbonded dimer H3NHBr by pulsednozzle, Fourier
transform microwave spectroscopy of ammonium bromide vapor
N. W. Howard and A. C. Legon
Citation: The Journal of Chemical Physics 86, 6722 (1987); doi: 10.1063/1.452371
View online: http://dx.doi.org/10.1063/1.452371
View Table of Contents: http://scitation.aip.org/content/aip/journal/jcp/86/12?ver=pdfcov
Published by the AIP Publishing
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This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP:
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This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP:
131.252.200.218 On: Sun, 30 Nov 2014 02:46:01

This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP:
131.252.200.218 On: Sun, 30 Nov 2014 02:46:01

This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP:
131.252.200.218 On: Sun, 30 Nov 2014 02:46:01

This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP:
131.252.200.218 On: Sun, 30 Nov 2014 02:46:01

This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP:
131.252.200.218 On: Sun, 30 Nov 2014 02:46:01

This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP:
131.252.200.218 On: Sun, 30 Nov 2014 02:46:01