Semiclassical on-the-fly computation of the S(0)-->S(1) absorption spectrum of formaldehyde.

The anharmonic S(0)-->S(1) vibronic absorption spectrum of the formaldehyde molecule is computed on the fly using semiclassical dynamics. This first example of an on-the-fly semiclassical computation of a vibronic spectrum was achieved using a unit prefactor modified frozen Gaussian semiclassical propagator for the excited state. A sample of 6000 trajectories sufficed for obtaining a converged spectrum, which is in reasonable agreement with experiment. Similar agreement is not obtained when using a harmonic approximation for the spectrum, demonstrating the need for a full anharmonic computation. This first example provides a resolution of approximately 100 cm(-1). Potential ways of improving the methodology and obtaining higher resolution and accuracy are discussed.

[1]  Benjamin G. Levine,et al.  Implementation of ab initio multiple spawning in the Molpro quantum chemistry package , 2008 .

[2]  E. Pollak,et al.  Ab initio spectroscopy and photoinduced cooling of the trans-stilbene molecule. , 2008, The Journal of chemical physics.

[3]  G. Worth,et al.  Direct quantum dynamics using variational multi-configuration Gaussian wavepackets. Implementation details and test case. , 2007, Physical chemistry chemical physics : PCCP.

[4]  H. Meyer,et al.  Theoretical investigation of intramolecular vibrational energy redistribution in highly excited HFCO. , 2006, The Journal of chemical physics.

[5]  M. Head‐Gordon,et al.  Curvy-steps approach to constraint-free extended-Lagrangian ab initio molecular dynamics, using atom-centered basis functions: convergence toward Born-Oppenheimer trajectories. , 2004, The Journal of chemical physics.

[6]  Hans-Dieter Meyer,et al.  Intramolecular vibrational energy redistribution in toluene: a nine-dimensional quantum mechanical study using the MCTDH algorithm , 2004 .

[7]  Haobin Wang,et al.  Semiclassical simulation of absorption spectra for a chromophore coupled to an anharmonic bath , 2004 .

[8]  E. Pollak,et al.  A prefactor free semiclassical initial value series representation of the propagator. , 2004, The Journal of chemical physics.

[9]  H. Meyer,et al.  Intramolecular vibrational energy redistribution in the highly excited fluoroform molecule: a quantum mechanical study using the multiconfiguration time-dependent Hartree algorithm. , 2004, The Journal of chemical physics.

[10]  F. Grossmann,et al.  Long-time and unitary properties of semiclassical initial value representations. , 2003, The Journal of chemical physics.

[11]  Filipp Furche,et al.  Adiabatic time-dependent density functional methods for excited state properties , 2002 .

[12]  G. Scuseria,et al.  Ab initio molecular dynamics: Propagating the density matrix with Gaussian orbitals , 2001 .

[13]  M. Thoss,et al.  Semiclassical description of nonadiabatic quantum dynamics: Application to the S1–S2 conical intersection in pyrazine , 2000 .

[14]  T. Martínez,et al.  Electronic absorption and resonance Raman spectroscopy from ab initio quantum molecular dynamics , 1999 .

[15]  Burke,et al.  Generalized Gradient Approximation Made Simple. , 1996, Physical review letters.

[16]  R. Ahlrichs,et al.  Treatment of electronic excitations within the adiabatic approximation of time dependent density functional theory , 1996 .

[17]  R. Ahlrichs,et al.  STABILITY ANALYSIS FOR SOLUTIONS OF THE CLOSED SHELL KOHN-SHAM EQUATION , 1996 .

[18]  P. Bruna,et al.  The Spectroscopy of Formaldehyde: III. Out-of-Plane Potentials and Geometry Optimizations for Singlet States , 1996 .

[19]  D. Manolopoulos,et al.  APPLICATION OF THE FROZEN GAUSSIAN APPROXIMATION TO THE PHOTODISSOCIATION OF CO2 , 1995 .

[20]  B. Roos,et al.  A theoretical determination of the electronic spectrum of formaldehyde , 1995 .

[21]  A. Schäfer,et al.  Fully optimized contracted Gaussian basis sets of triple zeta valence quality for atoms Li to Kr , 1994 .

[22]  J. B. Foresman,et al.  Excited states of carbonyl compounds. 1. Formaldehyde and acetaldehyde , 1993 .

[23]  Lorenz S. Cederbaum,et al.  Multiconfigurational time‐dependent Hartree study of complex dynamics: Photodissociation of NO2 , 1992 .

[24]  Wang,et al.  Accurate and simple analytic representation of the electron-gas correlation energy. , 1992, Physical review. B, Condensed matter.

[25]  Trygve Helgaker,et al.  Integration of the classical equations of motion on ab initio molecular potential energy surfaces using gradients and Hessians: application to translational energy release upon fragmentation , 1990 .

[26]  U. Manthe,et al.  The multi-configurational time-dependent Hartree approach , 1990 .

[27]  Shaul Mukamel,et al.  Eigenstate‐free, Green function, calculation of molecular absorption and fluorescence line shapes , 1986 .

[28]  Car,et al.  Unified approach for molecular dynamics and density-functional theory. , 1985, Physical review letters.

[29]  E. Kluk,et al.  A semiclasical justification for the use of non-spreading wavepackets in dynamics calculations , 1984 .

[30]  P. Jensen,et al.  The geometry and the inversion potential function of formaldehyde in the Ã1A2 and ã3A2 electronic states , 1982 .

[31]  S. J. Strickler,et al.  Absolute vibronic intensities in the 1A2 .rarw. 1A1 absorption spectrum of formaldehyde , 1982 .

[32]  Eric J. Heller,et al.  Frozen Gaussians: A very simple semiclassical approximation , 1981 .

[33]  Hm Henk Buck,et al.  Ab initio CI calculation of the vibrational structure of the 1(nπ*) transition in formaldehyde , 1978 .

[34]  Edward K. C. Lee,et al.  Single vibronic level photochemistry of formaldehydes in the ? 1A2 state: Radiative and nonradiative processes in H2CO, HDCO, and D2CO , 1978 .

[35]  E. Heller.  Photofragmentation of symmetric triatomic molecules: Time dependent picture , 1978 .

[36]  E. Heller.  Quantum corrections to classical photodissociation models , 1978 .

[37]  E. Yeung.  Radiative pathways in formaldehyde , 1973 .

[38]  J. B. Coon,et al.  Rotational constants and geometrical structure of the 1A2 and 3A2 states of H2CO and D2CO , 1969 .