Vibrational spectroscopy of the ammoniated ammonium ions NH sub 4 sup + (NH sub 3 ) sub n (n = 1-10)

Journal Article · Thu Mar 21 00:00:00 EST 1991 · Journal of Physical Chemistry; (United States)

DOI:https://doi.org/10.1021/j100159a020· OSTI ID:5757071

Price, J M; Crofton, M W; Lee, Y T ^[1]

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1. Lawrence Berkeley Lab., CA (United States) Univ. of California, Berkeley (United States)

The gas-phase vibration-internal rotation spectra of mass-selected ammoniated ammonium ions, NH{sub 4}{sup +}(NH{sub 3}){sub n} (for n = 1-10), have been observed from 2600 to 4000 cm{sup {minus}1}. The spectra show vibrational features that have been assigned to modes involving both the ion core species, NH{sub 4}{sup +}, and the first shell NH{sub 3} solvent molecules. Nearly free internal rotation of the solvent molecules about their local C{sub 3} axes in the first solvation shell has been observed in the smaller clusters (n = 1-6). For the larger clusters studied (n = 7-10) the spectra converge, with little difference between clusters differing by one solvent molecule. For these clusters, the spectrum in the 3200-3500 cm{sup {minus}1} region is quite similar to that of liquid ammonia, and the entire region of 2600-3500 cm{sup {minus}1} also bears considerable resemblance to the spectra of ammonium salts dissolved in liquid ammonia under some chemical conditions. This indicates the onset of a liquidlike environment for the ion core and first shell solvent molecules in clusters as small as NH{sub 4}{sup +}(NH{sub 3}){sub 8}.

• DOE Contract Number: AC03-76SF00098
• OSTI ID: 5757071
• Journal Information: Journal of Physical Chemistry; (United States), Journal Name: Journal of Physical Chemistry; (United States) Vol. 95:6; ISSN 0022-3654; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400102 -- Chemical & Spectral Procedures
400201* -- Chemical & Physicochemical Properties
AMMONIA
AMMONIUM COMPLEXES
CATIONS
CHARGED PARTICLES
COMPLEXES
ENERGY LEVELS
EXCITED STATES
HYDRIDES
HYDROGEN COMPOUNDS
INFRARED SPECTRA
IONIZATION
IONS
MASS SPECTROSCOPY
MATHEMATICAL MODELS
MULTIPOLES
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
QUADRUPOLES
ROTATIONAL STATES
SOLID CLUSTERS
SOLVATION
SPECTRA
SPECTROSCOPY
SYMMETRY
VIBRATIONAL STATES