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81.
里德堡原子由于具有体积大、寿命长、易极化及在外电场中能级易于操控等特点, 已经成为了目前物理学领域研究的热点之一. 本文在磁光阱中实验测量了铯原子15P3/2和16P3/2态的Stark光谱,根据光谱给出了15P3/2和16P3/2|m|=1/2 Stark态在0-1400 V/cm场强范围适用的Stark 能量和偶极矩的经验性解析表达式; 用数值方法求解薛定谔方程获得了这些态的Stark能量、偶极矩和电子几率密度分布. 电子几率密度分布定性说明了计算的偶极矩矢量的方向是正确的. 计算的Stark能量、偶极矩与实验结果相一致. 相似文献
82.
The quantum swap gate is one of the most useful gates for quantum computation. Two-qubit entanglement and a controlled-NOT quantum gate in a neutral Rydberg atom system have been achieved in recent experiments. It is therefore very interesting to propose a scheme here for swapping a quantum state between two trapped neutral atoms via the Rydberg blockade mechanism. The atoms interact with a sequence of laser pulses without individual addressing. The errors of the swap gate due to imprecision of pulse length, finite Rydberg interaction, and atomic spontaneous emission are discussed. 相似文献
83.
Signals of ultracold plasma are observed by two-photon
ionization of laser-cooled caesium atoms in a magneto-optical trap.
Recombination of ions and electrons into Rydberg atoms during the
expansion of ultracold plasma is investigated by using
state-selective field ionization spectroscopy. The dependences of
recombination on initial electron temperature (1--70 K) and initial
ion density ($ \sim $10$^{10}$ cm$^{ - 3})$ are investigated. The
measured dependence on initial ion density is $N^{1.547\pm 0.004}$
at a delay time of 5 $\mu $s. The recombination rate rapidly
declines as initial electron temperature increases when delay time
is increased. The distributions of Rydberg atoms on different values
of principal quantum number $n$, i.e. $n=30$--60, at an initial
electron temperature of 3.3 K are also investigated. The main
experimental results are approximately explained by the three-body
recombination theory. 相似文献
84.
The spectra of Rydberg hydrogen atom in magnetic fields have been calculated using linear variational method with B-splines basis functions [Acta Phys. Sin. 55 (2006) 3380]. Based on these calculations we have done some statistics analysis about the high Rydberg energy levels. The nearest-neighbor energy spacing distribution and the 3-statistics have been shown about diamagnetic Rydberg hydrogen atom with the magnetic field being 0.6 T and 6 T. The phenomena of multiply crossing, multiply anti-crossing, and the mixed of crossing and anti-crossing of energy levels have appeared in this paper. For both cases, in range of lower energy, the energy 1evel statistics properties close to Poisson distribution. With the increasing of the energy, the energy level statistics properties are away to Poisson distribution and tend to Wigner distribution step by step. 相似文献
85.
U. Galster P. Kaminski M. Beckert H. Helm U. Müller 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,17(3):307-318
We have performed kinematically complete investigations of molecular photodissociation of triatomic hydrogen in a fast beam
translational spectrometer recently built in Freiburg. The apparatus allows us to investigate laser-induced dissociation of
neutral molecules into two, three, or more neutral products. The fragments are detected in coincidence and their vectorial
momenta in the center-of-mass frame are determined. We demonstrate the potential of the method at the fragmentation of the
3 s
2
A
1
′
(
N
= 1,
K
= 0) state of triatomic hydrogen. In this state, three-body decay into ground state hydrogen atoms H+H+H, two-body predissociation
into H+H
2
(v
,
J), and photoemission to the H
3
ground state surface with subsequent two-body decay are competing channels. In the case of two-body predissociation, we determine
the rovibrational population in the H
2
(v
,
J) fragment. The vibrational distribution of H
2
is compared with approximate theoretical predictions. For three-body decay, we measure the six-fold differential photodissociation
cross-section. To determine accurate final state distributions, the geometric collection efficiency of the apparatus is calculated
by a Monte Carlo simulation, and the raw data are corrected for apparatus efficiency. The final state momentum distribution
shows pronounced correlation patterns which are characteristic for the dissociation mechanism. For a three-body decay process
with a discrete kinetic energy release we have developed a novel data reduction procedure based on the detection of two fragments.
The final state distribution determined by this independent method agrees extremely well with that observed in the triple-coincidence
data. In addition, this method allows us to fully explore the phase space of the final state and to determine the branching
ratios between the two- and three-body decay processes.
Received 29 March 2001 相似文献
86.
利用高分辨的交叉分子束装置研究了F+H2(v=0,j=0, 1)反应在碰撞能1.27 kcal/mol下的动力学行为, 获得了产物HF(v′=1,2,3)转动态分辨的微分散射截面.当反应物H2 处于不同转动量子态j=0和1时,产物HF(v′=2)的散射角分布都主要表现为后向散射,但HF(v′=2)的转动态布居与反应物的转动量子态密切相关,转动激发的H2分子将产生转动“更热”的HF(v′=2) 产物.另外,对于HF(v′=3)产物通道,由于slow-down机理的影响,当H2布居于j=0时前向散射表现更显著. 相似文献
87.
The allyl radical was produced in molecular beam by pyrolysis of allyl iodide. The vibronic spectra from ground state to six
new electronic states of the allyl radical at 6–8 eV, π →3dxz, π →3dxy and π →ns (n=4, 6, 7, 8) were observed firstly with the aid of time-of-flight mass spectros copy and resonance-enhanced multiphoton ionization
technique. Vibrational progression ofv
7(C3 bend) with gross spacing of about 430 cm−1 was observed inns Rydberg states. The adiabatic ionization potential of the allyl radical was obtained to be (65641 ± 20) cm−1 ((8.138 ± 0.002) eV) by fitting the term values ofns (n=4,6,7,8) Rydberg states with Rydberg formula. 相似文献
88.
Isolated-core-excitation (ICE) scheme and autoionization detection
are employed to study the bound Rydberg states of europium atom. The
high-lying states with odd parity have been measured using the
autoionization detection method with three different excitation
paths via 4f76s6p[ 8P5/2], 4f76s6p[ 8P7/2]
and 4f76s6p[ 8P9/2] intermediate states, respectively. In
this paper the spectra of bound Rydberg states of Eu atom are
reported, which cover the energy regions from 36000~cm-1 to
38250~cm-1 and from 38900~cm-1 to 39500 cm-1.
The study provides the information about level energy, the possible
J values and relative line intensity as well as the effective
principal quantum number n^* for these states. This work not only
confirms the previous results of many states, but also discovers 11
new Rydberg states of Eu atom. 相似文献
89.
A high resolution study of the high-n Rydberg H atom scattering with helium was carried out using the H atom Rydberg tagging time-of-flight technique. Differential cross sections were measured for scattering process of H(n)+He→H(n′)+He at the collision energy of 0.526 eV. Experimental result indicates that the scattered H(n′) product is mainly forward distributed, with signals observed in the wide range of angles at the sideway and forward scattering directions. At the sideway and forward directions, a lot of oscillatory structures in the angular distributions are present. Detailed analysis also shows that the principle quantum number, n, is not changed much for the Rydberg H atom at the forward scattering direction. This work provides a good test ground to investigate theoretically the exact collision dynamics between the high-n Rydberg H atom and the helium atom. 相似文献
90.
Radiative lifetimes of Rydberg 6pnd J=2 states of Pb I by multichannel quantum defect theory
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Energy levels of the odd-parity 6pnd J=2 Rydberg states of Pb I are analysed by the multichannel quantum defect theory (MQDT) in the frame of a five-channel three-limit calculation model. With optimal MQDT parameters, channel admixture coefficients are obtained and used to calculate the theoretical lifetimes of the levels by comparing to the previously measured lifetimes. The predicted lifetimes for higher-lying Rydberg states are given and discussed. These predicted lifetimes are very different from those obtained by the four-channel two-limit model pl:eviously used, which means that introduction of the additional interacting channel is important for studying the 6pnd J=2 Rydberg states of Pb I. 相似文献