36 research outputs found
Long-time and unitary properties of semiclassical initial value representations
We numerically compare the semiclassical ``frozen Gaussian'' Herman-Kluk
propagator [Chem. Phys. 91, 27 (1984)] and the ``thawed Gaussian'' propagator
put forward recently by Baranger et al. [J. Phys. A 34, 7227 (2001)] by
studying the quantum dynamics in some nonlinear one-dimensional potentials. The
reasons for the lack of long time accuracy and norm conservation in the latter
method are uncovered. We amend the thawed Gaussian propagator with a global
harmonic approximation for the stability of the trajectories and demonstrate
that this revised propagator is a true alternative to the Herman-Kluk
propagator with similar accuracy.Comment: 14 pages, 4 figures, corrected typos and figure 1 (d
Relations between matrix elements of different weak interactions and interpretation of the PNC and EDM measurements in atoms and molecules
The relations between matrix elements of different P- and T-odd weak
interactions are derived.
We demonstrate that similar relations hold for parity nonconserving (PNC)
transition amplitudes and electron electric dipole moments (EDM) of atoms and
molecules. This allows to express P- and T-odd effects in many-electron systems
caused by different symmetry-breaking mechanisms via each other using simple
analytical formulas. We use these relations for the interpretation of the
anapole moment measurements in cesium and thallium and for the analysis of the
relative contributions of the scalar-pseudoscalar CP-odd weak interaction and
electron EDM to the EDM of Cs, Tl, Fr and other atoms and many polar molecules
(YbF, PbO, ThO, etc.). Model-independent limits on electron EDM and the
parameter of the scalar-pseudoscalar CP-odd interaction are found from the
analysis of the EDM measurements for Tl and YbF.Comment: 10 pages, 1 figure, 4 tables. Table IV is correcte
Electron recombination, photoionization and scattering via many-electron compound resonances
Highly excited eigenstates of atoms and ions with open f shell are chaotic
superpositions of thousands, or even millions of Hartree-Fock determinant
states. The interaction between dielectronic and multielectronic configurations
leads to the broadening of dielectronic recombination resonances and relative
enhancement of photon emission due to opening of thousands of radiative decay
channels. The radiative yield is close to 100% for electron energy . 1 eV and
rapidly decreases for higher energies due to opening of many autoionization
channels. The same mechanism predicts suppression of photoionization and
relative enhancement of the Raman scattering. Results of our calculations of
the recombination rate are in agreement with the experimental data for W20+ and
Au25+.Comment: Physical Review
Semiclassical initial value calculations of collinear helium atom
Semiclassical calculations using the Herman-Kluk initial value treatment are
performed to determine energy eigenvalues of bound and resonance states of the
collinear helium atom. Both the configuration (where the classical motion
is fully chaotic) and the configuration (where the classical dynamics is
nearly integrable) are treated. The classical motion is regularized to remove
singularities that occur when the electrons collide with the nucleus. Very good
agreement is obtained with quantum energies for bound and resonance states
calculated by the complex rotation method.Comment: 24 pages, 3 figures. Submitted to J. Phys.