Theoretical study on ammonia cluster ions: Nature of thermodynamic magic number

Hiromi Nakai, Touichirou Goto, Takashi Ichikawa, Yoshiki Okada, Takaaki Orii, Kazuo Takeuchi

    Research output: Contribution to journalArticle

    15 Citations (Scopus)

    Abstract

    Stable geometries and electronic structures of ammonia cluster ions NH4/+(NH3)(n-1) (n = 1-17) are investigated by the ab initio theory in order to clarify the origin of the observed magic number. Since the ammonium ion NH4/+ brings about a large attraction to ammonia monomers, the stable geometries of NH4/+(NH3)(n-1) (n = 1-17) have shell structures around the ion. The calculated binding energy, which well reproduces the experimental ones, decreases monotonically as the cluster size increases. Gibbs free energies are also estimated with the use of the calculated electronic and vibrational energies. The Gibbs free energy curve with respect to the cluster size gives a minimum at n = 5 in comparatively wide temperature and pressure region, which corresponds to the experimental magic number. The minimum is found to be due to two competitive factors; that is, the nonlinear aspect of the binding energy and the linear instability of the translational entropy as the cluster size increases. (C) 2000 Elsevier Science B.V.

    Original languageEnglish
    Pages (from-to)201-210
    Number of pages10
    JournalChemical Physics
    Volume262
    Issue number2-3
    DOIs
    Publication statusPublished - 2000 Dec 15

    Fingerprint

    Ammonia
    ammonia
    Thermodynamics
    Gibbs free energy
    Ions
    Binding energy
    thermodynamics
    ions
    Geometry
    binding energy
    Ammonium Compounds
    Electronic structure
    Entropy
    geometry
    Monomers
    attraction
    monomers
    entropy
    electronic structure
    curves

    ASJC Scopus subject areas

    • Physical and Theoretical Chemistry
    • Spectroscopy
    • Atomic and Molecular Physics, and Optics

    Cite this

    Theoretical study on ammonia cluster ions : Nature of thermodynamic magic number. / Nakai, Hiromi; Goto, Touichirou; Ichikawa, Takashi; Okada, Yoshiki; Orii, Takaaki; Takeuchi, Kazuo.

    In: Chemical Physics, Vol. 262, No. 2-3, 15.12.2000, p. 201-210.

    Research output: Contribution to journalArticle

    Nakai, H, Goto, T, Ichikawa, T, Okada, Y, Orii, T & Takeuchi, K 2000, 'Theoretical study on ammonia cluster ions: Nature of thermodynamic magic number', Chemical Physics, vol. 262, no. 2-3, pp. 201-210. https://doi.org/10.1016/S0301-0104(00)00307-4
    Nakai, Hiromi ; Goto, Touichirou ; Ichikawa, Takashi ; Okada, Yoshiki ; Orii, Takaaki ; Takeuchi, Kazuo. / Theoretical study on ammonia cluster ions : Nature of thermodynamic magic number. In: Chemical Physics. 2000 ; Vol. 262, No. 2-3. pp. 201-210.
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    AU - Ichikawa, Takashi

    AU - Okada, Yoshiki

    AU - Orii, Takaaki

    AU - Takeuchi, Kazuo

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