DEFINITION OF A PERIODIC METHYL TORSIONAL COORDINATE IN THE S-0 STATE OF ACETALDEHYDE

被引：11

作者：

MUNOZCARO, C ^{[1
]}

NINO, A ^{[1
]}

MOULE, DC ^{[1
]}

机构：

[1] BROCK UNIV,DEPT CHEM,ST CATHARINES,ON L2S 3A1,CANADA

来源：

JOURNAL OF MOLECULAR STRUCTURE | 1995年 / 350卷 / 01期

关键词：

D O I：

10.1016/0022-2860(94)08457-S

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：

Torsional energy levels in acetaldehyde have been calculated at the MP2(full)/6-311G(d,p) level with full molecular relaxation for analyzing the loss of symmetry of the methyl group, It is shown that the usual definition for the rotational angle using a dihedral angle is an approximation, The use of asymmetric models for torsion fails to reproduce the degeneracy of the torsional levels and it is necessary to define a new three-fold torsional coordinate. Two approaches have been used. First, the use of selected conformations or energy averages which lead to energy levels within 6 cm(-1) of the experimental results, Second, the generation of a three-fold potential function considering the coupling with the remaining vibrations, This method produces energy levels in very good agreement with the experimental values.

引用

页码：83 / 89

页数：7

共 22 条

[1]

Lin, Swalen, Rev. Mod. Phys., 31, (1959)

[2]

Lister, McDonald, Owen, Internal Rotation and Inversion, (1978)

[3]

Ozkabak, Philis, Goodman, J. Am. Chem. Soc., 112, (1990)

[4]

Ozkabak, Goodman, Chem. Phys. Lett., 176, (1991)

[5]

Goodman, Ozkabak, J. Mol. Struct. (Theochem), 261, (1992)

[6]

Ozkabak, Goodman, J. Phys. Chem., 96, (1992)

[7]

Leszczynski, Goodman, J. Chem. Phys., 99, (1993)

[8]

Smeyers, Senent, Botella, Moule, J. Chem. Phys., 98, (1993)

[9]

Nino, Munoz-Caro, Moule, Wagging and torsion vibronic structure in the T1 .rarw. S0 electronic spectrum of acetaldehyde, The Journal of Physical Chemistry, 98, (1994)

[10]

Munoz-Caro, Nino, Moule, Chem. Phys., 186, (1994)

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