Rotational molecular dynamics of laser-manipulated bromotrifluoromethane studied by x-ray absorption
- Argonne National Laboratory, Argonne, Illinois 60439 (United States)
We present a computational study of the rotational molecular dynamics of bromotrifluoromethane (CF{sub 3}Br) molecules in gas phase. The rotation is manipulated with an off-resonant 800 nm laser. The molecules are treated as rigid rotors. Frequently, we use a computationally efficient linear rotor model for CF{sub 3}Br, which we compare with selected results for full symmetric-rotor computations. The expectation value <cos{sup 2} {theta}>(t) is discussed. Especially, the transition from impulsive to adiabatic alignment, the temperature dependence of the maximally achievable alignment, and its intensity dependence are investigated. In a next step, we examine resonant x-ray absorption as an accurate tool to study laser manipulation of molecular rotation. Specifically, we investigate the impact of the x-ray pulse duration on the signal (particularly its temporal resolution) and study the temperature dependence of the achievable absorption. Most importantly, we demonstrated that using picosecond x-ray pulses, one can accurately measure the expectation value <cos{sup 2} {theta}>(t) for impulsively aligned CF{sub 3}Br molecules. We point out that a control of the rotational dynamics opens up a novel way to imprint shapes onto long x-ray pulses on a picosecond time scale. For our computations, we determine the dynamic polarizability tensor of CF{sub 3}Br using ab initio molecular linear-response theory in conjunction with wave function models of increasing sophistication: Coupled-cluster singles (CCS), second-order approximate coupled-cluster singles and doubles (CC2), and coupled-cluster singles and doubles (CCSD)
- OSTI ID:
- 21254769
- Journal Information:
- Journal of Chemical Physics, Vol. 129, Issue 13; Other Information: DOI: 10.1063/1.2987365; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
Similar Records
An x-ray probe of laser-aligned molecules
An x-ray probe of laser-aligned molecules.
Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ABSORPTION
BROMINATED ALIPHATIC HYDROCARBONS
FLUORINATED ALIPHATIC HYDROCARBONS
LASER RADIATION
MOLECULAR DYNAMICS METHOD
PHOTON-MOLECULE COLLISIONS
POLARIZABILITY
ROTATIONAL STATES
TEMPERATURE DEPENDENCE
TENSORS
WAVE FUNCTIONS
X RADIATION
X-RAY SPECTRA