Article

A Multireference Configuration Interaction Investigation of the Excited-State Energy Surfaces of Fluoroethylene (C 2 H 3 F)

Institute for Theoretical Chemistry, University of Vienna, Währingerstrasse 17, A-1090 Vienna, Austria.
The Journal of Physical Chemistry A (Impact Factor: 2.78). 07/2005; 109(23):5168-75. DOI: 10.1021/jp050834+
Source: PubMed

ABSTRACT Multireference configuration interaction with singles and doubles (MR-CISD) calculations has been performed for the optimization of conical intersections and stationary points on the fluoroethylene excited-state energy surfaces. For the planar ground state geometry, the vertical spectrum including 3s and 3p Rydberg states was calculated. From this geometry, a rigid torsion around the CC bond strongly reduces the energy gap between S0 and S1 states. Furthermore, a search for the minimum of the crossing seam shows that there exists a conical intersection close to the twisted structure and two additional ones for cis and trans pyramidalized structures. These three intersections are connected by the same seam. We have shown that the Hula-Twist process is an alternative way to the direct CC twisting in order to reach this part of the seam. Other conical intersections were also located in the CH3CF and CH2FCH, H-migration, and C(3v) structures. The photodynamics of the system is discussed based on topological features of these intersections.

0 Followers
 · 
159 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Multireference configuration interaction calculations have been performed on the excited state energy surfaces of the methyleneimmonium cation using recently developed methods for the computation of analytic gradients and nonadiabatic coupling terms. Excited-state structures and minima on the crossing seam have been determined. It was found that the topology of the methyleneimmonium surfaces is qualitatively different from that of the isoelectronic ethylene. In the former case a conical intersection between the S, and ground states is found for the twisting motion around the CN bond, whereas a more complicated motion including pyramidalization and hydrogen-transfer is needed in case of ethylene.
    Computational Science and Its Applications - ICCSA 2005, International Conference, Singapore, May 9-12, 2005, Proceedings, Part I; 01/2005
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Recent advances in the generation of sub-fs extreme ultraviolet pulses and attosecond metrology have opened up the possibility to trace the time evolution of electronic wave packets inside atoms in pump-probe experiments. We investigate the feasibility of observing the buildup of a Fano resonance in the time domain by attosecond streaking techniques. A time-resolved resonance is initialized by a sub-fs extreme ultraviolet-pump pulse in the presence of a synchronized phase-controlled probe laser pulse. The time evolution of the coherent superposition of resonant state and continuum is mapped onto a modulation of the electron spectrum as a function of the time delay between pump and probe pulse. (super-)Coster-Kronig transitions with lifetimes of approximately 400 asec( are identified as prime candidates.
    Physical Review Letters 02/2005; 94(2):023002. DOI:10.1103/PhysRevLett.94.023002 · 7.51 Impact Factor
Show more

Preview

Download
2 Downloads
Available from