Accurate evaluation of internal energy level sums and densities including anharmonic oscillators and hindered rotors

Journal of Chemical Physics - Tập 58 Số 6 - Trang 2438-2445 - 1973
Stephen E. Stein1, B. S. Rabinovitch1
1Department of Chemistry, University of Washington, Seattle, Washington 98195

Tóm tắt

The calculation of molecular energy level sums and densities is necessary for the treatment of many physical and chemical problems including reaction rates. An extension of Beyer and Swinehart's algorithm for directly computing harmonic oscillator eigenstate sums and densities is described. With this new algorithm it is possible to compute exact or near-exact energy level sums and densities for degrees of freedom such as free and hindered rotors and anharmonic oscillators so long as the energy levels for each degree of freedom can be specified. Computer calculation by this technique is practical even for large molecules up to all chemically interesting energies and error is confined to small rounding errors. Results by this algorithm are compared to values of energy level sums that have been given in the literature by various alternative approximate treatments and permit more rigorous testing of the latter and assessment of the approximations involved.

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Tài liệu tham khảo

1951, J. Phys. Colloid Chem., 58, 894

1952, J. Chem. Phys., 20, 359, 10.1063/1.1700424

1963, J. Chem. Phys., 38, 783, 10.1063/1.1733764

1962, J. Am. Chem. Soc., 84, 4215, 10.1021/ja00881a006

1959, J. Chem. Phys., 30, 735, 10.1063/1.1730036

1961, J. Chem. Phys., 35, 2250, 10.1063/1.1732253

1963, J. Chem. Phys., 38, 2466, 10.1063/1.1733526

1964, J. Chem. Phys., 41, 1883, 10.1063/1.1726175

1968, J. Chem. Phys., 48, 1427

1939, J. Chem. Phys., 1, 1097

1959, J. Chem. Phys., 31, 1380, 10.1063/1.1730603

1963, Mol. Phys., 7, 101

1962, J. Chem. Phys., 37, 168, 10.1063/1.1732944

1963, J. Chem. Phys., 39, 3258, 10.1063/1.1734187

1967, J. Chem. Phys., 40, 3736

1971, Chem. Rev., 71, 339, 10.1021/cr60272a001

1970, J. Chem. Phys., 52, 113, 10.1063/1.1672655

1963, J. Chem. Phys., 39, 1577, 10.1063/1.1734483

1965, J. Chem. Phys., 43, 2153, 10.1063/1.1697098

1968, J. Chem. Phys., 49, 4187, 10.1063/1.1670734

1971, Mol. Phys., 20, 695, 10.1080/00268977100100661

1964, J. Chem. Phys., 40, 1461, 10.1063/1.1725346

1940, Phys. Rev., 57, 1006, 10.1103/PhysRev.57.1006

Thông tin
Thông tin xuất bản

Journal of Chemical Physics

Tập 58 Số 6

2438-2445

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