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VADIM L. STAKHURSKY , VLADIMIR A. LOZOVSKY, C. BRADLEY MOORE, TERRY A. MILLER

SIMULATIONS OF VIBRONIC LEVELS IN DEGENERATE ELECTRONIC STATES IN THE PRESENCE OF JAHN-TELLER COUPLING – EXPANSION OF PES THROUGH THIRD ORDER. VADIM L. STAKHURSKY , VLADIMIR A. LOZOVSKY, C. BRADLEY MOORE, TERRY A. MILLER

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VADIM L. STAKHURSKY , VLADIMIR A. LOZOVSKY, C. BRADLEY MOORE, TERRY A. MILLER

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  1. SIMULATIONS OF VIBRONIC LEVELS IN DEGENERATEELECTRONIC STATES IN THE PRESENCE OF JAHN-TELLER COUPLING – EXPANSION OF PES THROUGH THIRD ORDER VADIM L. STAKHURSKY, VLADIMIR A. LOZOVSKY, C. BRADLEY MOORE, TERRY A. MILLER Laser Spectroscopy Facility, Department of Chemistry, The Ohio State University 120 W. 18th Avenue, Columbus OH 43210.

  2. Motivation • Jahn-Teller distortion can significantly affect the characteristics of the molecule, e. g. rotational and vibrational spectra, partition function, rate of chem. reaction, enthalpy • There is a group of C3v molecules exhibiting Jahn-Teller effect (CH3O, CF3O, CH3S, CF3S, in the ground X2E state • CdCH3, MgCH3, ZnCH3 in the excited A2E state); • D3h molecules Na3, Ag3, Au3 with JT distorted structure • 3. Their vibronic structure is not completely understood, partially because of the computational complexity of the Jahn-Teller problem

  3. Harmonic potential JT distorted potential

  4. Spin-vibronic Hamiltonian e Standard: e+ e- const Additional term: where

  5. SOCJT(*) as a tool for JT problem analysis • What is SOCJT? • Fortran code for multidimensional Jahn-Teller problem with/without spin-orbit interaction • SOCJT gives: • Positions of spin-vibronic levels of the molecule in degenerate electronic state • Insight into composition of the level in terms of harmonic oscillator quantum numbers |n, l> • providing a tool for “labeling”of the levels • Calculates vibronic spectrum for absorption or emission experiments (A-E electronic transition, some limitations apply) • SOCJT input: • PES parameters up two third order: • Harmonic frequencies ωi and anharmonisities • Linear JT parameters Di • Quadratic JT parameters Ki and cross-quadratic terms for interaction of degenerate vibrations • Bilinear terms for coupling of symmetric and degenerate modes bij • Fermi iteraction terms • Terms non-diagonal in the projection of the electronic orbital momentum: • Spin-Orbit coupling parameter aze.

  6. SOCJT GUI hybrid capabilities SOCJT code is interfaced to spectra simulation and visualization package SpecView • The features of the product: • Simulate vibronic structure in degenerate electronic state of a C3v molecule with up to 3 • Jahn-Teller active e vibrational modes and up to 3 totally symmetric a modes • Simulate intensities of vibrational features observed in dispersed fluorescence (DF) and • absorption spectra • Fast calculation of spectra (2-5 sec for region up to 3000 cm-1 in methoxy) • Ability to run non-linear least square fit of simulated lines to frequencies of observed features • (Levenberg-Marquardt method) • .

  7. Vibrational frequencies of CH3O 1362 cm-1 1047 cm-1 2840a cm-1 C-O stretch symmetric C-H stretch CH3 umbrella 2774 cm-1 653 cm-1 1487 cm-1 asymmetric C-H stretch scissors CH3 rock aS. C. Foster, P. Misra, T.-Y. Lin, C. P. Damo, C. C. Carter, and T. A. Miller, J. Phys. Chem. 92, 5914 (1988).

  8. Dispersed Fluorescence spectra of methoxy radical 3361 pumped Experiment Simulation 3351 pumped Experiment Simulation Energy relative to vibrationless level, cm-1

  9. Dispersed Fluorescence spectra of methoxy radical 35 pumped Experiment Simulation 3341 pumped Experiment Simulation Energy relative to vibrationless level, cm-1

  10. Numerical calculations Dispersed Fluorescence spectrum of methoxy radical, 3141 pumped experiment b14= 53 cm-1 b14= 35 cm-1 b14= 15 cm-1 b14=0, K4=0.025 Spin-orbit, No JT b14 – bilinear parameter of coupling of symmetric CH stretch (v1) with asymmetric CH stretch (v4)

  11. Determined constants and comparison with ab-initio aT. A. Barckholtz and T. A. Miller, J. Phys. Chem. A 103, 2321 (1999). cU. Höper, P. Botschwina and H. Köppel, J. Chem. Phys. 112, 4132 (2000) and J. Schmidt-Klügmann, H. Köppel, S. Schmatz and P. Botschwina, Chem. Phys. Lett. 369, 21 (2003). cThis value was introduced phenomenologically to match the separation of the vibrationless spin-doublet in workb. dA. V. Marenich and J. E. Boggs, J. Chem. Phys. 122(2), 024308 (2005).

  12. Comparison of experimental and calculated vibronic energies of CH3O ( ), including spin-orbit coupling effects a SEP data by Temps and coworkers6, if not marked otherwise b current work, the constants were slightly adjusted to compensate for a wrong sign of the K5 constant in work by T. Barckholtz et al.20 c J. Schmidt-Klugmann et al.22 dA. Marenich et al.23 e Analysis of the DF data in this work f Averaged position from this DF work and work by Foster et al.12

  13. Conclusions and future work • We extended SOCJT Fortran code to include potential energy • surface terms up to third order. High-throughput GUI • C++/Fortran hybrid is developed for the simulation of the • vibrational structure of the electronic transitions (2A-2E) • 2. In our future work we will extend the approach to allow for high-throughput • simulations of the 2E-2E electronic transitions THANK YOU

  14. ACKNOWLEDGMENTS Ohio State University

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