NC5NC:: results of coupled cluster calculations and an unusual anharmonicity effect

被引:14
作者
Botschwina, P [1 ]
Oswald, R [1 ]
机构
[1] Univ Gottingen, Inst Phys Chem, D-37077 Gottingen, Germany
关键词
D O I
10.1016/S0009-2614(00)00156-1
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
On the basis of CCSD(T) calculations, an accurate equilibrium geometry has been established for linear NC5NC: R-1e(NC) = 1.1615 Angstrom, R-2e = 1.3705 Angstrom, R-3e = 1.2134 Angstrom, R-4e = 1.3607 Angstrom, R-5e = 1.2102 Angstrom, R-6e = 1.3047 Angstrom and R-7e(NC) = 1.1831 Angstrom, with uncertainties on the order of 0.0005 Angstrom. The ground-state rotational constant is predicted to be 580.2 +/- 0.2 MHz and the equilibrium dipole moment is obtained to be mu(e) = 1.38 D. In agreement with matrix isolation IR spectroscopy, only three intense vibrational transitions are calculated for the most abundant isotopomer between 2000 and 2300 cm(-1) Inclusion of anharmonicity effects is mandatory to obtain this result; an unusual anharmonicity effect between the fundamentals nu(1) and nu(2) is predicted. Isotopic substitution significantly changes the intensities of the two stretching vibrational bands with highest wavenumber. (C) 2000 Elsevier Science B.V. All rights reserved.
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页码:587 / 594
页数:8
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