Theoretical study of bifurcating reaction paths

Theoretical study has been given on bifurcating reaction paths where the intrinsic reaction path (IRP) has a valley-ridge inflection (VRI) point on the way from transition state to product, and leads to another first-order saddle point which connects two symmetrically equivalent products. To extract dynamically important regions in the configuration space between the VRI point and products, a group of steepest descent paths are calculated starting from zero-point energy regions at the VRI point, and the obtained configuration space is analyzed in terms of the reaction coordinate and the normal coordinate. The method is applied to Berry pseudorotations in SiH4F− and PH4F, H3CO→H2COH, and cyclopropylidene→allene, by employing the second-order Mo/ller–Plesset and complete active space self-consistent field ab initio molecular orbital calculations. It is shown that the extension of bifurcating reaction paths largely depends on the position of the VRI point on the IRP. For the respective reactions, non-totally...

[1]  Keiji Morokuma,et al.  Potential energy characteristics and energy partitioning in chemical reactions: Abinitio MO study of four‐centered elimination reaction CH3CH2F→CH2=CH2+HF , 1980 .

[2]  W. Kraus,et al.  Reaction dynamics on bifurcating potential energy surfaces , 1986 .

[3]  Peter M. W. Gill,et al.  An algorithm for the location of branching points on reaction paths , 1988 .

[4]  E. Muetterties,et al.  Idealized polytopal forms. Description of real molecules referenced to idealized polygons or polyhedra in geometric reaction path form , 1974 .

[5]  Reaction path curvature effects in the isomerization of the methoxy radical , 1985 .

[6]  J. Ross,et al.  On symmetry properties of reaction coordinates , 1974 .

[7]  J. Pople,et al.  Self‐Consistent Molecular Orbital Methods. IV. Use of Gaussian Expansions of Slater‐Type Orbitals. Extension to Second‐Row Molecules , 1970 .

[8]  R. Pearson.  Orbital symmetry rules for unimolecular reactions , 1972 .

[9]  J. Pople,et al.  Self—Consistent Molecular Orbital Methods. XII. Further Extensions of Gaussian—Type Basis Sets for Use in Molecular Orbital Studies of Organic Molecules , 1972 .

[10]  John E. Adams,et al.  Reaction path Hamiltonian for polyatomic molecules , 1980 .

[11]  R. Bader.  VIBRATIONALLY INDUCED PERTURBATIONS IN MOLECULAR ELECTRON DISTRIBUTIONS , 1962 .

[12]  Kimihiko Hirao,et al.  APPROACHES TO BIFURCATING REACTION PATH , 1996 .

[13]  B. Roos,et al.  A complete active space SCF method (CASSCF) using a density matrix formulated super-CI approach , 1980 .

[14]  Wolfgang Quapp,et al.  Gradient extremals and valley floor bifurcations on potential energy surfaces , 1989 .

[15]  Mark S. Gordon,et al.  General atomic and molecular electronic structure system , 1993, J. Comput. Chem..

[16]  K. Hirao,et al.  Theoretical study of the reactions of pentacoordinated trigonal bipyramidal phosphorus compounds: PH5, PF5, PF4H, PF3H2, PF4CH3, PF3(CH3)2, P(O2C2H4)H3, P(OC3H6)H3, and PO5H4- , 1992 .

[17]  R. Squires,et al.  Hypervalent silicon hydrides: SiH5 , 1986 .

[18]  Jun-qiang Sun,et al.  Quadratic steepest descent on potential energy surfaces. I. Basic formalism and quantitative assessment , 1993 .

[19]  Dietmar Heidrich,et al.  The Reaction path in chemistry : current approaches and perspectives , 1995 .

[20]  The structural stability principle and branching points on multidimensional potential energy surfaces , 1987 .

[21]  Tsuneo Hirano,et al.  Mechanism of bifurcation along the reaction path: An application in the case of thioformaldehyde , 1993 .

[22]  M. Plesset,et al.  Note on an Approximation Treatment for Many-Electron Systems , 1934 .

[23]  Klaus Ruedenberg,et al.  The ring opening of cyclopropylidene to allene: global features of the reaction surface , 1991 .

[24]  R. Stephen Berry,et al.  Correlation of Rates of Intramolecular Tunneling Processes, with Application to Some Group V Compounds , 1960 .

[25]  D. Heidrich,et al.  Properties of Chemically Interesting Potential Energy Surfaces , 1991 .

[26]  Akitomo Tachibana,et al.  Stability of the reaction coordinate in the unimolecular reaction of thioformaldehyde , 1985 .

[27]  H. Bürgi.  Stereochemistry of Reaction Paths as Determined from Crystal Structure Data—A Relationship between Structure and Energy , 1975 .

[28]  Mark S. Gordon,et al.  A detailed analysis of pseudorotation in PH4F , 1992 .

[29]  Ralph G. Pearson,et al.  Symmetry rules for chemical reactions , 1971 .

[30]  H. Bernhard Schlegel,et al.  Some thoughts on reaction-path following , 1994 .

[31]  L. Salem,et al.  Vibrational modes, orbital symmetries, and unimolecular reaction paths , 1969 .