The pseudo-Jahn—Teller effect: a CASSCF diagnostic

A simple test for the pseudo-Jahn-Teller effect is proposed, based on the behaviour of a CASSCF frequency calculation when symmetry is restricted. The test suggests that the pseudo-Jahn-Teller effect operates at the D2h transition structure of S0 pentalene and the D8h transition structure of S0 cyclooctatetraene. The D4h transition structure of S0 cyclooctatetraene is not subject to a pseudo-Jahn-Teller distortion according to this test. Our interpretation of the pseudo-Jahn-Teller effect differs from the conventional one based on a single-transition (CIS-like) approximation.

[1]  S. Koseki,et al.  Energy Component Analysis of the Pseudo Jahn-Teller Effect in Pentalene and Heptalene , 1992 .

[2]  T. Barckholtz.  Quantitative insights about molecules exhibiting Jahn-Teller and related effects , 1998 .

[3]  M. Robb,et al.  A CASSCF study of the cyclopentadienyl radical: conical intersections and the Jahn–Teller effect , 1999 .

[4]  I. Bersuker,et al.  Modern aspects of the Jahn-Teller effect theory and applications to molecular problems. , 2001, Chemical reviews.

[5]  Antonio Morreale,et al.  POTENTIAL ENERGY SURFACE OF CYCLOOCTATETRAENE , 1998 .

[6]  Zhendong Zhu,et al.  Pentalene: Formation, Electronic, and Vibrational Structure , 1997 .

[7]  Peter R. Taylor,et al.  Molecular properties from perturbation theory: a unified treatment of energy derivatives , 1985 .

[8]  H. Schaefer,et al.  Interpretation of excited state Hartree–Fock analytic derivative anomalies for NO2 and HCO2 using the molecular orbital Hessian , 1991 .

[9]  M. Pryce,et al.  Studies of the Jahn-Teller effect. I. A survey of the static problem , 1957, Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences.

[10]  C. Trindle.  Planarization of 8π Rings. I. Confirmation of a speculation by Ermer on the ground state of a strained cyclooctatetraene and studies on analogous oxepins , 1998 .

[11]  C. Párkányi.  Theoretical organic chemistry , 1998 .

[12]  H. A. Jahn,et al.  Stability of Polyatomic Molecules in Degenerate Electronic States. I. Orbital Degeneracy , 1937 .

[13]  D. Yarkony,et al.  On the evaluation of nonadiabatic coupling matrix elements using SA‐MCSCF/CI wave functions and analytic gradient methods. I , 1984 .

[14]  L. Paquette.  The Current View of Dynamic Change within Cyclooctatetraenes , 1993 .

[15]  R. Pearson.  Symmetry rule for predicting molecular structures , 1969 .

[16]  E. Davidson,et al.  Symmetry breaking in polyatomic molecules: real and artifactual , 1983 .

[17]  P. Schwerdtfeger,et al.  Trends in Inversion Barriers of Group 15 Compounds. 2. Ab-Initio and Density Functional Calculations on Group 15 Fluorides , 1994 .

[18]  D. Yarkony.  Conical Intersections: The New Conventional Wisdom , 2001 .

[19]  Thom Vreven,et al.  Potential-energy surfaces for ultrafast photochemistry Static and dynamic aspects , 1998 .

[20]  M. Page,et al.  Multireference CI Gradients and MCSCF Second Derivatives. , 1984 .

[21]  W. C. Lineberger,et al.  Transition-State Spectroscopy of Cyclooctatetraene , 1996, Science.

[22]  K. B. Wiberg.  Antiaromaticity in monocyclic conjugated carbon rings. , 2001, Chemical reviews.

[23]  David A. Hrovat,et al.  CASSCF calculations find that a D8h geometry is the transition state for double bond shifting in cyclooctatetraene , 1992 .

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

[25]  Michael J. Bearpark,et al.  Potential energy surfaces of pseudoaromatic molecules: An MMVB and CASSCF study of pentalene , 1996 .

[26]  M. Nguyen,et al.  INVERSION PROCESSES IN PHOSPHINES AND THEIR RADICAL CATIONS : WHEN IS A PSEUDO-JAHN-TELLER EFFECT OPERATIVE? , 1998 .

[27]  Thom Vreven,et al.  A direct derivative MC-SCF procedure , 1996 .

[28]  S. Zilberg,et al.  Two-State Model of Antiaromaticity: The Low Lying Singlet States , 1998 .

[29]  Michael J. Bearpark,et al.  A direct method for the location of the lowest energy point on a potential surface crossing , 1994 .

[30]  Marco Garavelli,et al.  Intrinsically Competitive Photoinduced Polycyclization and Double-Bond Shift through a Boatlike Conical Intersection. , 2001, Angewandte Chemie.

[31]  Sastry,et al.  The radical cation of syn-tricyclooctadiene and its rearrangement products , 2000, Chemistry.