1,850 research outputs found
QPROP: A Schroedinger-solver for intense laser-atom interaction
The Qprop package is presented. Qprop has been developed to study laser-atom
interaction in the nonperturbative regime where nonlinear phenomena such as
above-threshold ionization, high order harmonic generation, and dynamic
stabilization are known to occur. In the nonrelativistic regime and within the
single active electron approximation, these phenomena can be studied with Qprop
in the most rigorous way by solving the time-dependent Schr\"odinger equation
in three spatial dimensions. Because Qprop is optimized for the study of
quantum systems that are spherically symmetric in their initial, unperturbed
configuration, all wavefunctions are expanded in spherical harmonics.
Time-propagation of the wavefunctions is performed using a split-operator
approach. Photoelectron spectra are calculated employing a window-operator
technique. Besides the solution of the time-dependent Schr\"odinger equation in
single active electron approximation, Qprop allows to study many-electron
systems via the solution of the time-dependent Kohn-Sham equations.Comment: 40 pages, LaTeX; to obtain the QPROP source code visit
http://www.qprop.de, accepted for publication in Computer Physics
Communication
An analytical study of liquid outflow from cylindrical tanks during weightlessness Final report
Liquid outflow from cylindrical tanks during weightlessnes
Angular distribution studies on the two-photon ionization of hydrogen-like ions: Relativistic description
The angular distribution of the emitted electrons, following the two-photon
ionization of the hydrogen-like ions, is studied within the framework of second
order perturbation theory and the Dirac equation. Using a density matrix
approach, we have investigated the effects which arise from the polarization of
the incoming light as well as from the higher multipoles in the expansion of
the electron--photon interaction. For medium- and high-Z ions, in particular,
the non-dipole contributions give rise to a significant change in the angular
distribution of the emitted electrons, if compared with the electric-dipole
approximation. This includes a strong forward emission while, in dipole
approxmation, the electron emission always occurs symmetric with respect to the
plane which is perpendicular to the photon beam. Detailed computations for the
dependence of the photoelectron angular distributions on the polarization of
the incident light are carried out for the ionization of H, Xe, and
U (hydrogen-like) ions.Comment: 16 pages, 4 figures, published in J Phys
Nonsequential Double Recombination in Intense Laser Fields
A second plateau in the harmonic spectra of laser-driven two-electron atoms
is observed both in the numerical solution of a low-dimensional model helium
atom and using an extended strong field approximation. It is shown that the
harmonics well beyond the usual cut-off are due to the simultaneous
recombination of the two electrons, which were emitted during different,
previous half-cycles. The new cut-off is explained in terms of classical
trajectories. Classical predictions and the time-frequency analysis of the ab
initio quantum results are in excellent agreement. The mechanism corresponds to
the inverse single photon double ionization process in the presence of a (low
frequency) laser field.Comment: 4 pages, RevTeX, v2 with an extended strong field approximation
treatment of the process; instead, v1 describes an attosecond control scheme
to enhance the proces
Relativistic and retardation effects in the two--photon ionization of hydrogen--like ions
The non-resonant two-photon ionization of hydrogen-like ions is studied in
second-order perturbation theory, based on the Dirac equation. To carry out the
summation over the complete Coulomb spectrum, a Green function approach has
been applied to the computation of the ionization cross sections. Exact
second-order relativistic cross sections are compared with data as obtained
from a relativistic long-wavelength approximation as well as from the scaling
of non-relativistic results. For high-Z ions, the relativistic wavefunction
contraction may lower the two-photon ionization cross sections by a factor of
two or more, while retardation effects appear less pronounced but still give
rise to non-negligible contributions.Comment: 6 pages, 2 figure
Deuteron Momentum Distribution in KD2HPO4
The momentum distribution in KD2PO4(DKDP) has been measured using neutron
Compton scattering above and below the weakly first order
paraelectric-ferroelectric phase transition(T=229K). There is very litte
difference between the two distributions, and no sign of the coherence over two
locations for the proton observed in the paraelectric phase, as in KH2PO4(KDP).
We conclude that the tunnel splitting must be much less than 20mev. The width
of the distribution indicates that the effective potential for DKDP is
significantly softer than that for KDP. As electronic structure calculations
indicate that the stiffness of the potential increases with the size of the
coherent region locally undergoing soft mode fluctuations, we conclude that
there is a mass dependent quantum coherence length in both systems.Comment: 6 pages 5 figure
Динаміка екологічної політики і правосвідомості в переломленні норм кримінального права
Коваль М. П. Динаміка екологічної політики і правосвідомості в переломленні норм кримінального права : автореф. дис. ... канд. юрид. наук : 23.00.02 / М. П. Коваль; кер. роботи Ю. Є. Полянський; Нац. ун.-т "Одеська юридична академія". – Одеса, 1998. – 19 с.Дисертація в вигляді рукопису на здобуття вченого ступеня кандидата юридичних наук по спеціальності 23.00. 02. - Політичні інститути і процеси. Одеська державна юридична академія. - Одеса, 1998 р.
Досліджуються проблеми ефективності екологічної політики при
опосередкуванні правовими засобами. Захищаються теоретичні положення,
що стосуються кримінально-екологічної охорони. На цій основі
формулюються поняття кримінально-екологічної правосвідомості, поняття
об'єкта екологічного захисту і охорони. Ставиться проблема уніфікації у
вигляді Екологічного кодексу в Україні. Пропонуються рекомендації по
ефективній екологічній політиці шляхом вдосконалення кримінально-екологічного законодавства.Диссертация в виде рукописи на соискание ученой степени кандидата юридических наук по специальности 23.00.02. - Политические институты и политические процессы. Одесская
государственная юридическая академия . г. Одесса, 1998г.
Исследуются проблемы эффективности экологической политики при
опосредовании правовыми методами. Защищаются теоретические положения,
касающиеся уголовно-экологической
охраны.
На этой основе формулируются
понятия уголовно-экологического правосознания, понятия объекта
экологической защиты и охраны. Ставится проблема унификации в виде
Экологического кодекса в Украине. Предлагаются рекомендации по
эффективной экологической политике путем совершенствования уголовно-экологического законодательства.The
thesis
is being submitted
for
a master of laws' degree
in handwritting 23.00.02.- Political institution and process. The Odessa State
juridical Academy. 1998.
The question of ecologic policy
efficiency
and are being researched by means
juridical methods. The theoretical principles concerning criminal law - ecology
protection. On this base the concepts of criminal law - ecologic lawconciousness
as
well as
those of
subject
of ecologic protection and
defence.
The task of unification
in the
form
Ukraine's ecologic Code
is
being
set.
The recommendations on
efficient
ecologic policy by improvement of criminal law-ecologic legigation and being
proposed {put forward for consideration}
Loneliness and Deprivation: The Case of Roman Catholic Priests
Using Roman Catholic Priests as a test in order to control for deprivation in relationships of intimacy while maximizing the need for social network relationships, an examination was made of their differential experience of loneliness.
The evidence suggested repeatedly that priests were more likely to experience loneliness as a serious problem when they perceived that the social network which they regarded as most significant in their lives (the Church) placed some kind of structural limitation on the extent of their involvement in it. Factors, for example, which help determine the individual priest\u27s place in the structure of the Church are: type of assignment, length of time ordained, and degree of integration into the network through mutual commitment; all of these factors correlate significantly with the experience of loneliness.
For priests experiencing serious loneliness, there were further significant correlations with a perceived deficit in intimacy, an expressed need for sexual intimacy, a desire to marry, and more frequent dating behavior.
While causal sequences could not be established with certainty, the use of Guttman scaling techniques and a logical ordering of the variables suggests strongly that an emotional response (in this case an exaggerated search for intimate relationships) may have been triggered by social deprivation (network exclusion) rather than by an emotional deprivation (in intimacy) as might have been expected.
Such a possibility has far-reaching implications and calls for further research. If an exaggerated search for intimate relationships can be triggered by social network deprivation, that might shed light on a variety of other phenomena such as promiscuity and rape, especially in urban, industrialized societies whose character is such that secondary relationehips become more pervasive and achieve such great importance in the minds and daily lives of the people
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