排序方式: 共有39条查询结果,搜索用时 203 毫秒
31.
M. Altmann F. v. Feilitzsch J. Hhne M. L. Sarsa J. Schnagl S. Wnninger 《Nuclear Physics B - Proceedings Supplements》1999,70(1-3)
An improvement of the statistical and systematic uncertainty beyond the level achieved in GALLEX is an essential prerequisite for GNO. As major contributions to these errors are associated with the detection of the EC-decay of 71Ge in miniaturized gas counters, low temperature calorimetric detectors might provide a promising alternative for a later phase of GNO. We report first results achieved in measurements of the EC-decaying isotopes 71Ge and 37Ar with cryogenic calorimeters. 相似文献
32.
A simple and accurate variational wave function in which the dependence in the interelectronic distance is factored is proposed to describe S-type states of two-electron atomic systems. We introduce a parameterization which generalizes the previous ones used in this same framework and which allows us to obtain in a simple way the wave function of both symmetric and antisymmetric excited states. We performed a systematic analysis of some exact properties such as the virial theorem and the cusp conditions and a study of both the one- and two-body densities. Finally, a comparison among the different correlation functions for these states was performed for helium. © 1998 John Wiley & Sons, Inc. Int J Quant Chem 68: 405–413, 1998 相似文献
33.
F. J. Gálvez E. Buendía P. Maldonado A. J. Sarsa 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,50(3):229-235
A systematic application of the optimized effective potential equations
for atoms in both the non-relativistic and relativistic cases is carried out.
The ground state energy and the ionization potential of the
atoms Li through to Ra is obtained.
In the relativistic case, a trial wave function including all of the jj
configurations that contribute to the ground state term within the electronic
configuration are included.
The results are compared with the corresponding Hartree-Fock and
Dirac-Hartree-Fock values. 相似文献
34.
We have solved the atomic Hartree–Fock equations by using the algebraic approach, expanding the single-particle radial wave function in terms of a modified Gaussian type orbitals (GTOs) basis. Several atomic properties such as Kato's cusp condition for the electron density or the correct asymptotic behavior of the electron momentum density distribution are accurately verified. Additionally the energy of the atomic ground state can be obtained by using a smaller number of basis functions than in standard GTO expansions. This study has been performed for several atoms of the first three rows. © 1997 John Wiley & Sons, Inc. Int J Quant Chem 65 : 59–64, 1997 相似文献
35.
Within the diffusion Monte Carlo approach, we have determined the structure of isotopically pure and mixed helium droplets doped with one magnesium atom. For pure (4)He clusters, our results confirm those of Mella et al. [J. Chem. Phys. 123, 054328 (2005)] that the impurity experiences a transition from a surface to a bulk location as the number of helium atoms in the droplet increases. Contrarily, for pure (3)He clusters Mg resides in the bulk of the droplet due to the smaller surface tension of this isotope. Results for mixed droplets are presented. We have also obtained the absorption spectrum of Mg around the 3s3p?(1)P(1) ← 3s(2)?(1)S(0) transition. 相似文献
36.
Jiang H Sarsa A Murdachaew G Szalewicz K Bacić Z 《The Journal of chemical physics》2005,123(22):224313
We present a rigorous theoretical study of the solvation of (HCl)(2) and (HF)(2) by small ((4)He)(n) clusters, with n=1-14 and 30. Pairwise-additive potential-energy surfaces of He(n)(HX)(2) (X=Cl and F) clusters are constructed from highly accurate four-dimensional (rigid monomer) HX-HX and two-dimensional (rigid monomer) He-HX potentials and a one-dimensional He-He potential. The minimum-energy geometries of these clusters, for n=1-6 in the case of (HCl)(2) and n=1-5 for (HF)(2), correspond to the He atoms in a ring perpendicular to and bisecting the HX-HX axis. The quantum-mechanical ground-state energies and vibrationally averaged structures of He(n)(HCl)(2) (n=1-14 and 30) and He(n)(HF)(2) (n=1-10) clusters are calculated exactly using the diffusion Monte Carlo (DMC) method. In addition, the interchange-tunneling splittings of He(n)(HCl)(2) clusters with n=1-14 are determined using the fixed-node DMC approach, which was employed by us previously to calculate the tunneling splittings for He(n)(HF)(2) clusters, n=1-10 [A. Sarsa et al., Phys. Rev. Lett. 88, 123401 (2002)]. The vibrationally averaged structures of He(n)(HX)(2) clusters with n=1-6 for (HCl)(2) and n=1-5 for (HF)(2) have the helium density localized in an effectively one-dimensional ring, or doughnut, perpendicular to and at the midpoint of the HX-HX axis. The rigidity of the solvent ring varies with n and reaches its maximum for the cluster size at which the ring is filled, n=6 and n=5 for (HCl)(2) and (HF)(2), respectively. Once the equatorial ring is full, the helium density spreads along the HX-HX axis, eventually solvating the entire HX dimer. The interchange-tunneling splitting of He(n)(HCl)(2) clusters hardly varies at all over the cluster size range considered, n=1-14, and is virtually identical to that of the free HCl dimer. This absence of the solvent effect is in sharp contrast with our earlier results for He(n)(HF)(2) clusters, which show a approximately 30% reduction of the tunneling splitting for n=4. A tentative explanation for this difference is proposed. The implications of our results for the interchange-tunneling dynamics of (HCl)(2) in helium nanodroplets are discussed. 相似文献
37.
38.
Bivash R Behera Subinit Roy P Basu M K Sharan S Jena M Satpathy SK Datta L Satpathy ML Chatterjee 《Pramana》1999,53(3):563-566
Time of flight and energy of fission fragments were measured using pulsed beam. Fission fragment mass and energy integrated
angular distributions were extracted. Fission fragment anisotropy was explained in the framework of saddle point model. 相似文献
39.
C. Bobin N. Coron G. Dambier E. García C. Goldbach D. Gonzlez J. Leblanc P. de Marcillac A. Morales J. Morales G. Nollez A. Ortiz de Solrzano J. Puimedn A. Salinas M. L. Sarsa S. Scopel J. A. Villar 《Nuclear Physics B - Proceedings Supplements》1999,70(1-3)
An experiment to look for light WIMPs with sapphire bolometers is to be installed in the Canfranc Underground Laboratory (at 2450 m.w.e) in the Spanish Pyrenees. In the first stage two small 25g bolometers with NTD-Ge sensors, operating at 25mK, with an energy threshold of 300eV and FWHM energy resolution of 120eV at 1.5keV will perform a background test experiment. The features of the bolometers, the radioactivity measurements of the components and the set-up and status of the experiment are reported. 相似文献