A direct method for the location of the lowest energy point on a potential surface crossing

Abstract We present a method, which avoids the use of Lagrange multipliers, for the optimisation of the lowest energy point of the intersection of two potential energy surfaces. The efficiency of this unconstrained algorithm is demonstrated for the n—2 intersection space of a conical intersection and the n—1 intersection space of the crossing of two states of different spin multiplicity.

[1]  I. N. Ragazos,et al.  A concerted nonadiabatic reaction path for the singlet Di-π-methane rearrangement , 1993 .

[2]  R. D. Poshusta,et al.  Excited potential energy hypersurfaces for H4. 2. "Triply right" (C2v) tetrahedral geometries. A possible relation to photochemical "cross-bonding" processes , 1977 .

[3]  W. Domcke,et al.  Ab initio investigation of potential‐energy surfaces involved in the photophysics of benzene and pyrazine , 1993 .

[4]  Josef Michl,et al.  Electronic aspects of organic photochemistry , 1990 .

[5]  I. N. Ragazos,et al.  Excited-state cis-trans isomerization of cis-hexatriene , 1994 .

[6]  Sushovan De,et al.  The mechanism of ground-state-forbidden photochemical pericyclic reactions: evidence for real conical intersections , 1990 .

[7]  Keiji Morokuma,et al.  Determination of the lowest energy point on the crossing seam between two potential surfaces using the energy gradient , 1985 .

[8]  H. C. Longuet-Higgins,et al.  Intersection of potential energy surfaces in polyatomic molecules , 1963 .

[9]  L. Salem.  Electrons in chemical reactions: First principles , 1982 .

[10]  D. Yarkony.  On the role of conical intersections of two potential energy surfaces of the same symmetry in photodissociation. I. CH3SH→CH3S+H and CH3+SH , 1994 .

[11]  Edward Teller,et al.  The Crossing of Potential Surfaces. , 1937 .

[12]  F. Bernardi,et al.  Modelling Photochemical Reactivity of Organic Systems — A New Challenge to Quantum Computational Chemistry , 1993 .

[13]  Ian J. Palmer,et al.  An MC-SCF study of the thermal and photochemical cycloaddition of dewar benzene , 1992 .

[14]  Ian J. Palmer,et al.  An MC-SCF Study of the S1 and S2 Photochemical Reactions of Benzene , 1993 .

[15]  Fernando Bernardi,et al.  Optimization and characterization of the lowest energy point on a conical intersection using an MC-SCF Lagrangian , 1992 .

[16]  I. N. Ragazos,et al.  Origin of the nonstereospecificity in the ring opening of alkyl-substituted cyclobutenes , 1992 .

[17]  H. Werner,et al.  Characterization of the S1–S2 conical intersection in pyrazine using ab initio multiconfiguration self‐consistent‐field and multireference configuration‐interaction methods , 1994 .

[18]  W. Domcke,et al.  Internal conversion funnel in benzene and pyrazine: adiabatic and diabatic representation , 1993 .

[19]  D. Yarkony,et al.  On the characterization of regions of avoided surface crossings using an analytic gradient based method , 1990 .

[20]  I. N. Ragazos,et al.  A new mechanistic scenario for the photochemical transformation of ergosterol: an MC-SCF and MM-VB [molecular mechanics-VB] study , 1992 .

[21]  F. Bernardi,et al.  Predicting forbidden and allowed cycloaddition reactions: potential surface topology and its rationalization , 1990 .

[22]  I. N. Ragazos,et al.  A conical intersection mechanism for the photochemistry of butadiene. A MC-SCF study , 1993 .

[23]  D. Yarkony,et al.  On the intersection of two potential energy surfaces of the same symmetry. Systematic characterization using a Lagrange multiplier constrained procedure , 1993 .

[24]  D. Yarkony,et al.  Systematic determination of intersections of potential energy surfaces using a Lagrange multiplier constrained procedure , 1993 .