首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 187 毫秒
1.
STRUCTURESANDINTERNALMOTIONOFANe3CLUSTERXieWenfangChenChuanyuDepartmentofPhysics,GuangzhouTeachers′colegeGuangzhou510400ABST...  相似文献   

2.
MEASUREMENTSOFFeANDCuK-ShelIONIZATIONCROSSSECTIONSBYSLOWELECTRONIMPACTLiTaihuaAnZhuLuoZhengmingCenterforRadiationPhysics,Ins...  相似文献   

3.
TOTALCROSSSECTIONMEASUREMENTSFORELECTRONSCATTERINGONMETHANEBETWEEN1AND50eVLiTaihuaYeRuiyingYangYongCenterforRadiationPhysics...  相似文献   

4.
POPULATIONDYNAMICSINTHEFOUR-PHOTONTHREE-STEPPHOTOIONIZATION¥ShiliangXie;DewuWang;ChuntionYing(DepartmentofEngineeringPhysics,...  相似文献   

5.
PUSHINGTHEENVELOPEINRAMANSPECTROSCOPYG.D.Pitt(UniversityofLeedsandRenishawplcU.K)NewtechniqueshavebeendevelopedforUVRamanmicr...  相似文献   

6.
CALCULATIONFORSTRETCHINGVIBRATIONALSPECTRUMOFCH4ChenXiangrongGouQingquanPangXiaofengInstituteofAtomicandMolecularScienceatHig...  相似文献   

7.
DEUTERIUMINFLUXPROFILEALONGTHEAPEXOFTHEUPPERX-POINTTILESINJET¥Y.K.Zhu(SouthwesternInstituteofPhysics,P.O.Box432,Chengdu610041...  相似文献   

8.
THEORETICALCALCULATIONOFATOMICANDMOLECULARDATAPeiChunchuanPurpleMountainObservatoryAcademiaSinicaNanjing210008ABSTRACTByusin...  相似文献   

9.
THERMALINSTABILITYOFD-TBURNINGPLASMAS¥B.R.SHIY.X.LONGH.G.ZHAO(SouthwesterninstituteofPhysics,P.O.Box432,Chengdu610041,Sichuan...  相似文献   

10.
AComparisonofSRSefectsbetweenUni┐andBi┐directionalWDMTransmisionSystemsZHANGKanXIELinzhenXUAnshiWUDeming(DepartmentofElectron...  相似文献   

11.
The angular distribution of the five-fold differential cross section for the electron impact double ionization of He (21 S) and He (23 S) has been studied. The kinematical conditions for maxima/minima in the angular distribution for the two cases have been compared. The two-step process for the double ionization is found to contribute very little in the triplet case.  相似文献   

12.
The yield of H(+) in the metastable He*(2(3)S, 1s2s) stimulated desorption (MSD) on an H2O/Na/Fe surface has been found to depend on the spin of the incident He*. By combination with the spin-resolved analysis for the surface electronic structure, it is indicated that the neutralization of the hole in the OH 3 sigma molecular orbital, which is created by the incident He*, by Na 3s electrons plays a crucial role in the spin polarization of the H (+) MSD intensity. The dependence of the spin polarization of H(+) MSD on the kinetic energy of the desorbed H(+) has been observed, and it is discussed based on the Menzel-Gomer-Readhead model.  相似文献   

13.
We observe vibrational states by photoassociation spectroscopy of cold He(2 ^{3}S) atoms. Photoassociation resonances are detected as peaks in the Penning ionization rate over a frequency range of 20 GHz below the atomic 2 ^{3}S_{1}-2 ^{3}P_{2} transition frequency. We have observed three vibrational series, of which two can be identified. A possible mechanism to explain the observed increase of the Penning ionization rate is discussed.  相似文献   

14.
Using a crossed-beam apparatus with a double hemispherical electron spectrometer, we have studied the spectrum of electrons released in thermal energy ionizing collisions of metastable He*(23S) atoms with ground state Yb(4f14 6s2 1S0) atoms, thereby providing the first Penning electron spectrum of an atomic target with 4f-electrons. In contrast to the Hel (58.4 nm) and NeI (73.6/74.4 nm) photoelectron spectra of Yb, which show mainly 4f- and 6s-electron emission in about a 5:1 ratio, the He*(23S) Penning electron spectrum is dominated by 6s-ionization, accompanied by some correlation-induced 6p-emission (8% Yb+(4f14 6p 2P) formation) and very little 4f-ionization (?2.5%). This astounding result is attributed to the electron exchange mechanism for He*(23S) ionization and reflects the poor overlap of the target 4f-electron wavefunction with the 1s-hole of He*(23S), as discussed on the basis of Dirac-Fock wave functions for the Yb orbitals and through calculations of the partial ionization cross sections involving semiempirical complex potentials. The presented case may be regarded as the clearest atomic example for the surface sensitivity of He*(23S) Penning ionization observed so far.  相似文献   

15.
We have calculated the3He(3He, 2p)4He and3H(3H, 2n)4He reaction cross sections at low energies within the microscopic multichannel resonating group method. For both reactions, we find good agreement with experiment. For the3H(3H, 2n)4He reaction, our calculated energy dependence reproduces that of each individual low-energy experimental data set, except for a normalization constant. Using this fact, we derive at a low-energy3H(3H, 2n)4He rate by taking the averaged mean of these fits.This work has been supported in part by the National Science Foundation, Grants PHY86-04197 and PHY88-17296.  相似文献   

16.
周丽霞  燕友果 《物理学报》2008,57(12):7619-7622
采用修正后的扭曲波玻恩近似(DWBA)理论,计算了共面不对称几何条件及大能量转移和小动量转移条件下的He(1s2),Ar(3p6)和Ar(2p6)(e, 2e)反应三重微分截面.将理论计算结果与实验结果及由Brauner,Briggs和Klar提出的BBK方法、标准的DWBA理论计算结果进行了比较,发现在共面不对称几何条件及大能量转移和小动量转移条件下,极化效应和后碰撞相互作用在He(1s2),Ar(3p6< 关键词: (e;2e)反应 极化效应 后碰撞相互作用 共面不对称几何条件  相似文献   

17.
Collisional ionization of styrene (phenylethylene), 2-vinylpyridine, and 4-vinylpyridine with metastable He*(23S) atoms were studied by means of collision-energy/electron-energy resolved two-dimensional Penning ionization electron spectroscopy. Collision energy dependence of partial ionization cross-sections, which reflects the anisotropic interactions between a He*(23S) atom and the target molecules, indicates that attractive interaction for the out-of-plane access of a He*(23S) atom to phenyl group is stronger than that for the out-of-plane access to vinyl group. Moreover, it was found for vinylpyridines that the attractive interaction around π electrons became weaker than that for styrene, and that the attractive interaction for the in-plane access to the nitrogen atom is stronger than that for out-of-plane π-directions. However, in 2-vinylpyridine, the hydrogen atom of vinyl group prevents a He*(23S) atom from approaching to the nitrogen atom along in-plane directions, and thus the attractive interactions around the nitrogen atom were shielded by the vinyl group. The experimentally observed anisotropic interactions were qualitatively supported with ab initio model interaction potential calculations between a Li (He*(23S)) atom and the target molecule. Concerning with electronic structures of investigated molecules, the assignment of Penning ionization electron spectrum for 4-vinylpyridine was discussed on the basis of different behavior of collision-energy dependence of partial ionization cross-sections, and the satellite ionization band in Penning ionization electron spectra was also reported for styrene.  相似文献   

18.
We have studied the stability of mixed (3)He/(4)He clusters in L=0 states by the diffusion Monte Carlo method, employing the Tang-Toennies-Yiu He-He potential. The clusters (3)He(4)He(N) and (3)He(2)(4)He(N) are stable for N>1. The lighter atoms tend to move to the surface of the cluster. The minimum number of 4He atoms able to bind three 3He atoms in a L=0 state is nine. Two of three fermionic helium atoms stay on the surface, while the third one penetrates into the cluster.  相似文献   

19.
The heat capacity of (3)He in (3)He-(4)He mixture films on a nuclepore substrate is reported over the temperature range 90相似文献   

20.
焦志莲 《大学物理》2012,(2):13-15,18
计算了敲出电子等能分享几何安排下,入射能量分别为5 599 eV和1 099 eV时He(e,3e)反应五重微分截面,并比较在He(e,3e)过程中散射粒子的相互作用和它们之间的干涉效应对五重微分截面的贡献.结果表明,理论计算数据在误差范围内与实验数据基本吻合,并且散射粒子的相互作用以及干涉效应对五重微分截面的影响都是不容忽视的.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号