排序方式: 共有41条查询结果,搜索用时 0 毫秒
1.
We reveal that for a realistic system, interference effects are obtained such as the suppression of central line and inner sidebands and the narrowing of the outer fluorescence sidebands. For this purpose, we consider a spontaneous decay from an excited state to a metastable state when the excited and metastable states are resonantly coupled to an auxiliary metastable state by a laser field and a microwave field, respectively. The fluorescence spectrum evolves from a five-peaked structure into a doublet of ultrasharp lines as the ratio of the laser field Rabi frequency to the microwave Rabi frequency is decreased. The physical origin is presented in terms of dressed states. 相似文献
3.
O. Budriga V. Florescu 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,41(2):205-210
We study Compton scattering on the ground state of the hydrogen atom in the presence of an intense low-frequency electric
field (the laser) of arbitrary polarization, for incident and scattered photons of energies around 15 keV. The adopted formalism
is the nonrelativistic one developed by Voitkiv et al. [J. Phys. B: At. Mol. Opt. Phys. 36, 1907 (2003)] and applied by them for a circularly polarized laser. We explore the spectrum and the electron energy distribution
in their dependence on the incident photon energy or electric field intensity, for different polarizations. 相似文献
4.
J.P. Santos F. Parente P. Indelicato 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1998,3(1):43-52
A theoretical study of the one- and two-photon spontaneous emission rates from the 2
s1/2 state of one-electron ions is presented. High-precision values of the relativistic emission rates for ions with nuclear charge
Z up to 100 are obtained through the use of finite basis sets for the Dirac equation constructed from B-splines. Furthermore,
we analyze the influence of the inclusion of quantum electrodynamics corrections in the initial and final state energies.
Received: 6 January 1998 / Accepted: 31 March 1998 相似文献
5.
R. Unanyan S. Guérin B. W. Shore K. Bergmann 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2000,8(3):443-449
In traditional schemes of multilevel multilaser excitation, each laser pulse interacts with only one pair of states, and the
rotating wave approximation (RWA) is applicable. Here we study the population transfer process in a three-state system when
each of the two lasers interacts with each of the pair of states and when the Rabi frequencies characterizing the interaction
strengths of the system are comparable to or larger than the difference of the transition frequencies. We show that complete
and robust population transfer is possible under conditions more general than those hitherto considered necessary for stimulated
Raman adiabatic passage (STIRAP) or for successive π pulses. Using adiabatic Floquet theory we show that successful population transfer can be interpreted as adiabatic passage
by means of a transfer state which connects the initial and final states. The Floquet picture offers a convenient interpretation
of the population transfer as accompanied by multiple absorption of photons from or emission into the laser fields. 相似文献
6.
F. Michelot M. Rey 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,44(3):467-495
Effective vibronic Hamiltonian models are built for E ⊗e Jahn-Teller systems and analytical solutions are
obtained through Lie algebraic methods. Although approximate, we show that these models allow in particular to recover the
possible ground state crossover when quadratic couplings are present. The equivalence of E ⊗e and G' ⊗e
vibronic systems in cubic symmetry is precisely established through a particular realization of the electronic operators for
an
orbital quadruplet. We show how this equivalence is broken by a rovibronic interaction which, for a G' ⊗e system, still
gives an exactly solvable model. 相似文献
7.
D. Khalil A. Makhoute A. Maquet G. Rahali M. Zitane 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,41(2):287-295
The dynamics of laser-assisted elastic collisions in
helium is studied using the second-order Born approximation.
Detailed calculations of the scattering amplitudes are performed
by using the Sturmian basis expansion. Differential cross sections
for elastic scattering with the net absorption/emission of up to
two photons are calculated for collision energies of 5 eV, 10 eV,
and 20 eV. We discuss the influence of the low-energy electrons on
the differential cross section (DCS) as a function of the
scattering angle for selected choices of the laser frequency and
the number of photons exchanged between the external field and
electron-helium system. 相似文献
8.
Stimulated resonant emission and stimulated Raman effects in sodium vapor in the presence of helium are investigated experimentally. The intensity dependence of these effects on the buffer gas and sodium vapor pressures, and on the intensity and detuning of the exciting radiation are obtained in experiment. Our experimental results agree with the most recent theoretical calculations.This work was carried out under the Polish Central Program of Fundamental Research CPBP 01.06 相似文献
9.
E. Cormier P. Lambropoulos 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1998,2(1):15-20
We report on observable new features related to ionization of atoms by laser pulses of only few cycles and some intensity.
We show that for particular photo-electron energies, the angular distribution becomes asymmetric and that this asymmetry is
related to the initial phase of the field.
Received: 4 November 1997/Revised: 21 January 1998/Accepted: 23 February 1998 相似文献
10.
A. Giardini A. Paladini F. Rondino S. Piccirillo M. Satta Ana R. Hortal M. Speranza 《Applied Physics A: Materials Science & Processing》2008,93(4):893-899
Resonant Two Photon Ionization (R2PI) spectroscopy has been applied to the study of host–guest interactions in molecular clusters
formed by supersonic exspansion. Here, the results of R2PI spectroscopy of the fluorinated organic molecules para and ortho-fluoro-sec-butylbenzene and their complexes with water and argon are reported and discussed. In particular, it is shown that the position
of the fluorine atom on the aromatic ring influences the formation of different kind of complexes (σ versus π) with argon and water. Ab initio calculations were performed to get insight into the molecular shape and the structure of
these clusters. 相似文献