Structure and dissociation energy of the weakly bound complex CH[sub 5][sup +](H[sub 2])
- Univ. of Georgia, Athens, GA (United States)
- Univ. of Georgia, Athens, GA (United States) Universitaet Erlangen-Nuernberg (Germany)
The possible low-lying stationary points of CH[sub 5][sup +](H[sub 2]) have been investigated using high level ab initio quantum mechanical techniques. All structures were optimized up to the TZ2P CISD level of theory. The global minimum structure (1) was also optimized at the TZ2P CCSD(T) and TZ2P+d CCSD levels. Four C[sub s] structures, which have H[sub 2] bound to one of two protons of the three-center-two-electron bond of the CH[sub 5][sup +] subunit, have essentially the same energy. Consequently, several internal degrees of freedom in CH[sub 5][sup +](H[sub 2]) are virtually completely unrestricted. We determined the dissociation energy D[sub 0] of CH[sub 5][sup +](H[sub 2]) to be 1.46 kcal/mol [TZ2P+d CCSD(T)]. Harmonic vibrational frequencies have been evaluated for all structures at the TZ2P SCF level of theory; for the energetically lowest-lying structure (1), we also determined the vibrational frequencies up to the TZ2P CCSD level. The H-H stretching frequency shift ([minus]83 cm[sup [minus]]) predicted theoretically is in excellent agreement with the recently determined experimental value ([minus]83.6 cm[sup [minus]1]). The average value of theoretical rotational constants for the energetically lowest lying stationary points (1-4) and one other minimum (7) compares moderately well with the experimental result. 35 refs., 2 figs., 9 tabs.
- DOE Contract Number:
- FG09-87ER13811
- OSTI ID:
- 5525680
- Journal Information:
- Journal of Physical Chemistry; (United States), Journal Name: Journal of Physical Chemistry; (United States) Vol. 97:47; ISSN JPCHAX; ISSN 0022-3654
- Country of Publication:
- United States
- Language:
- English
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400201* -- Chemical & Physicochemical Properties
661100 -- Classical & Quantum Mechanics-- (1992-)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
COMPLEXES
DATA
DISSOCIATION ENERGY
ENERGY
ENERGY LEVELS
EXCITED STATES
INFORMATION
MECHANICS
MOLECULAR STRUCTURE
NUMERICAL DATA
QUANTUM MECHANICS
REACTION INTERMEDIATES
THEORETICAL DATA
VIBRATIONAL STATES