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 31 毫秒
1.
激发态Na2与H2碰撞,使H2(v=3,J=3)得到布居,在H2和He总气压为800Pa及温度为700K的条件下,利用相干反斯托克斯拉曼散射(CARS)光谱技术研究了H2(3,3)与H2(He)间转动能量转移过程。改变CARS激光束与激发Na2的激光之间的延迟时间,测量He不同摩尔配比时H2(3,J)态CARS谱强度的时间演化,得到H2(3,3)的总弛豫速率系数分别为=(21±5)×10-13cm3s-1和=(5.6±1.6)×10-13cm3s-1。测量H2(3,J)各转动态的相对CARS谱强度,由速率方程分析,得到H2(3,3)+H2→H2(3,J)+H2中,对于J=2,4,转移速率系数分别为11±4和8.2±3.1cm3s-1。在H2(3,3)+He→H2(3,J)+He中,对于J=2,4,转移速率系数分别为3.1±1.2和2.1±0.7cm3s-1。对于H2(3,3),单量子弛豫׀∆J׀=1约占该态总弛豫率的90%。  相似文献   

2.
根据商群对称性分析法对MMTWD晶体的振动模作了理论计算.计算结果显示,通过实验可观察到的拉曼散射峰和红外反射带应分别不超过297和148个.运用实验的手段,分别测定晶体的拉曼光谱和红外光谱,给出了MMTWD晶体在50~3 000 cm-1范围内的拉曼光谱图和400~4 000 cm-1范围里的红外光谱图,并对光谱中的谱线作了指认.给出了MMTWD晶体的分子结构示意图,最终确定MMTWD晶体结构为三维网状结构,说明在众多新型光功能材料当中MMTWD晶体是一种更适合生长成较大尺寸且稳定性较好的非线性光学晶体,在光电子领域中具有良好的应用前景.  相似文献   

3.
用密度泛函(DFT)方法优化了配合物H3 PAuPh(a),(H3 Pau)2(1,4-C6 H4)2(b)的基态的几何结构,并用含时密度泛函方法计算了它们的吸收光谱.结果表明配合物a与b的最低能量吸收谱线的波长分别为257.5 nm和307.6nm,皆具有C(2p)→Au(6p)电荷转移参与下的Px(芳环)→px>(芳环)跃迁本质,并伴有Au(5d)→Au(6p)的金属中心电荷转移性质.配合物b是由两个配合物a相连接而成,配合物b的分子轨道也是由配合物a的分子轨道组合而成.由于轨道组合中存在px或Px相互作用,配合物b的最低能量吸收谱线的波长大于配合物a的相应值.  相似文献   

4.
《Surface science》1993,296(3):L33-L37
Most recent experimental work on H2 desorption from the monohydride Si(100) surface seems to point to a pairwise desorption mechanism involving the concerted desorption of two hydrogen atoms on different Si atoms of a single dimer. Using ab initio SCF and CI theory and a cluster model of the surface, the present work finds that the lowest energy pathway is symmetric rather than asymmetric. The desorption energy barrier is calculated to be 3.7 eV. Compared with an experimental value of 2.6 eV, the large barrier suggests that this direct desorption mechanism is not applicable. A multi-step desorption mechanism which involves a delocalized process in the formation of dihydride SiH2 and a localized desorption of H2 is proposed and is shown to explain the experimental observations.  相似文献   

5.
利用OPO激光激发光谱和三维荧光光谱研究了配合物Eu(C5H8NO3)2(C3H5N2)2Cl3·3H2O固体粉末在不同激发光源下的荧光特性,测试了不同浓度配合物水溶液的荧光光谱.固体荧光结果显示该配合物具有很好的荧光性能,当激发光波长为320-400nm时,产生波长分别为400-500nm、580-620nm及690-710nm的三个荧光区;当激发光波长为700-880nm时产生峰值为450nm升频转换荧光,激发光波长为700-800nm时产生峰值分别为590nm和615nm的升频转换荧光.溶液荧光结果表明在10-4-10-2mol/L浓度范围内荧光强度与溶液浓度呈正相关.对其可能的发光机制进行了探讨.  相似文献   

6.
以糖精钠(sac-Na)、丙氨酸和硝酸钴为原料合成得到糖精钴琥珀色块状晶体,采用红外、X射线单晶衍射对配合物进行了表征,该晶体属单斜晶系,空间群为P21/c,晶胞参数为:a=0.79269(5)nm,b=1.61407(10)nm,c=0.77026 (5) nm,α=90°,β=99.695(7)°,Ⅴ=0.97145 (11) nm3,Z=2,Dc=1.817g/cm3,F(000)=546,R=0.0278.结构分析表明,中心Co离子与4个O原子和两个N原子配位,处于四角双锥八面体配位环境中,4个水分子在赤道平面上与Co离子配位,晶胞中还包含有2个游离的结晶水,形成了含6个水分子的结晶物.  相似文献   

7.
磷酸盐激光玻璃聚(CH3)2 Si(OC2 H5)2防潮膜   总被引:1,自引:0,他引:1  
以(CH3)2Si(OC2H5)2为前驱体,采用溶胶-凝胶与有机合成相结合的方法,制得稳定性良好的涂膜液。采用旋转涂膜法在掺钕磷酸盐激光玻璃棒端面涂制防潮膜,膜层固化后透过率达96.5%,获得的膜层表面粗糙度优良,均方根表面粗糙度(RMS)为1.659nm,平均粗糙度(RA)平均为1.321nm;在激光波长1053nm,脉冲宽度1 ns条件下膜层的激光破坏闽值可达10~14 J/cm^2。经过“神光Ⅱ”高功率激光器物理实验运行,膜层使用期为五年,并且已经在我国“神光Ⅲ”原型装置上试用。  相似文献   

8.
The room temperature crystal structure of the inverse weberite ZnFeF5 (H2O)2 is refined from powder X-ray diffraction. The cell is orthorhombic (S.G. Imma, a = 7.475(1) →A, b = 10.766(1) →A, c = 6.594(1) →A, z = 4). Below TN = 9(2) K, ZnFeF5(H2O)2 becomes a 1-D antiferromagnet. This behaviour was characterized by susceptibility and magnetization measurements and Mössbauer spectroscopy. On the contrary, isotypic MnFeF5(H2O)2 is confrimed to be a ferrimagnet below Tc = 39.5(1)K. Its magnetic and Mössbauer characteristics are, above and below Tc,and agree with a 3-D magnetic character. Ferrimagnetism could be due to frustration effects as in previously described Fe2F5(H2O)2.  相似文献   

9.
电场诱导MgO材料吸附H2是一种有效的储氢方法,而较高的场强制约其广泛应用。本文在B3LYP/CC-PVTZ水平上对电场中 (MgO)2团簇的储氢性质进行了研究,结果表明仅需外加强度为0.005 a. u. 的电场,就能使其对单个H2在Mg/O上的吸附能由无电场时的-0.143/-0.091 eV提高到-0.202/-0.134 eV. 该场强远小于其他大尺寸MgO材料达到相同吸附强度所需的电场,表明降低材料尺寸是减少储氢所需电场强度的一种可能方法。计算还表明电场中(MgO)2最多能吸附8个H2,相应的质量密度达到16.7 wt%。  相似文献   

10.
Single crystals of [(R)-C5H14N2][Cu(SO4)2(H2O)4]·2H2O (1) were grown through the slow evaporation of a solution containing H2SO4, (R)-C5H12N2 and CuSO4·5H2O. These crystals spontaneously transform to [(R)-C5H14N2]2[Cu(H2O)6](SO4)3 (2) over the course of four days at room temperature. The same single crystal on the same mounting was used for the determination of the structure of (1) and the unit cell determination of (2). A second single crystal of the transformed batch has served for the structural determination of (2). Compound 1 crystallizes in the noncentrosymmetric space group P21 (No. 4) and consists of trimeric [Cu(SO4)2(H2O)4]2? anions, [(R)-C5H14N2]2+ cations and occluded water molecules. Compound 2 crystallizes in P21212 (No. 18) and contains [Cu(H2O)6]2+ cations, [SO4]2? anions and occluded water molecules. The thermal decompositions of compounds 1 and 2 were studied by thermogravimetric analyses and temperature-dependent X-ray diffraction.  相似文献   

11.
电场诱导MgO材料吸附H2是一种有效的储氢方法,而较高的场强制约其广泛应用。本文在B3LYP/CC-PVTZ水平上对电场中 (MgO)2团簇的储氢性质进行了研究,结果表明仅需外加强度为0.005 a. u. 的电场,就能使其对单个H2在Mg/O上的吸附能由无电场时的-0.143/-0.091 eV提高到-0.202/-0.134 eV. 该场强远小于其他大尺寸MgO材料达到相同吸附强度所需的电场,表明降低材料尺寸是减少储氢所需电场强度的一种可能方法。计算还表明电场中(MgO)2最多能吸附8个H2,相应的质量密度达到16.7 wt%。  相似文献   

12.
The structure of the mineral zeunerite (deposits at Rotava near Kraslice, Ore Mountains) was determined. The tetragonal unit cell, having the dimensionsa=7.105Å andc=17.704Å, contains two structure units of Cu(UO2)2(AsO4)28H2O. The space group isP42/nmc. The distribution of the atoms in the unit cell was determined from the Patterson projectionP(vw) and by means of (F 0-F c) synthesis. Meta-Zeunerite has a layer type structure. The sheets [(UO2)(AsO4)] are separated by layers containing the cations (Cu(H2O)4)2+ and molecules of water. The uranium is coordinated octahedrally with six oxygen atoms at distances: U-O1 1.94 Å, U-O2 1.78 Å, U-O3(4) 2.18 Å (4×). The uranyl radical O1-U-O2 is linear. In the tetrahedron AsO4 the interatomic distances are As-O 1.77 Å and the bond angles 102°, 102°, 113° and 113°. Each oxygen atom of the tetrahedron AsO4 is simultaneously bonded to the uranium atom. The bond angle As-O-U is 137°. The layers [(UO2)2(AsO4)] are bonded together by the cations (Cu(H2O)4)2+. The distances Cu-O1 and Cu-O2 are 2.55 and 2.58Å respectively. The structural changes during hydration and dehydration are explaned.
- Cu(UO2)2(AsO4)28 H2O
( , ). =7,105 Å,=17,704 Å Cu(UO2)2(AsO4)28 2O. P42/nmc. P(v w) (F 0-F c) . . , [(UO2)(AsO4)], , [u(2)4]2+ . : U-O1 1,94 Å, U-O2 1,78 Å, U-O3(4) 2,18 Å ( ). 1-U-2. AsO4 As- 1,77 Å -102°, 102°, 113° 113°. AsO4 . As--U 137°. [(UO2)2(AsO4)] [u(2O)4]2+. u-O1 2,55 Å, u-O2 2,58 Å. .


In conclusion the author thanks T. Veselská for assistance in the calculations and workers of the National Museum in Prague, and primarily Dr. ípek, for supplying the sample. The experimental work was carried out at the Department of Physics of the Natural Science Faculty of Komenský University.  相似文献   

13.
本文利用CCSD(T)/6-311++(3df,3pd)//B3LYP-D3/6-311++G(3df,3pd)+ 0.9686×ZPE理论方法对(H2O)n (n=1-3)和H2SO4存在与不存在的情况下,H2CO3气相分解反应机理进行了理论研究。计算结果表明(H2O)n (n=1-3)和H2SO4都能使H2CO3气相分解反应的能垒显著地降低,其催化能力按由强到弱的顺序是H2SO4>(H2O)2>(H2O)3>H2O。  相似文献   

14.
The 2H(d, γ)4He capture reaction and the 2H(d, p)3H and 2H(d, n)3He transfer reactions at very low energies are studied in an extended microscopic cluster model with a realistic nucleon–nucleon force. Our results show that the tensor force in realistic interactions plays an essential and indispensable role to reproduce the very low-energy astrophysical S factor of these reactions.  相似文献   

15.
The (2)H(d,p)(3)H, (2)H(d,n)(3)He, and (2)H(d,γ)(4)He reactions are studied at low energies in a multichannel ab initio model that takes into account the distortions of the nuclei. The internal wave functions of these nuclei are given by the stochastic variational method with the AV8' realistic interaction and a phenomenological three-body force included to reproduce the two-body thresholds. The obtained astrophysical S factors are all in very good agreement with the experiment. The most important channels for both transfer and radiative capture are identified by comparing to calculations with an effective central force. They are all found to dominate thanks to the tensor force.  相似文献   

16.
合成了配合物单晶[Zn(PSA)2(H2O)2],其中PSA-为4-苯基丁酸根.配合物为单斜晶系,Cc空间群,a=3.8340(11)nm,b=0.51865(15)nm,c=1.0734(3)nm.a=90°,β=103.064(4).,r=90°,C20H26O6Zn.Mr=427.79,Z=4,V=2.0791(10)nm3,D=1.212g/cm3,F(000)=900,-46≤h≤43,-4≤k≤6,-13≤l≤13,R1=0.0780,wR2=0.2029.PSA-以两个氧原子与中心离子Zn(Ⅱ)离子形成四元螯合环,PSA与PSA反式构型.配合物分子之间存在氢键弱相互作用.  相似文献   

17.
郭胜利 《波谱学杂志》1999,16(3):181-186
报道了Ni(C3H10N2)2NO2(ClO4)晶体在T=1.5K温度和W波段的ESR实验.建立了d8离子基态3A2(F)的零场分裂参量D,E,和g因子与斜方对称晶场势参量间的关系,并应用于Ni(C3H10N2)2NO2(ClO4)晶体.计算值与实验数据符合很好,表明所给关系式是合理的.  相似文献   

18.
采用单电子的双中心原子轨道强耦合方法,研究了1-100 碰撞体系的激发、俘获和失去电子总截面,并分别与前人的理论结果和实验结果进行了比较。研究表明,采用双中心原子轨道强耦合方法得到的 体系激发到 过程和失去电子过程的截面与实验符合很好。  相似文献   

19.
使用三维含时波包方法在两个势能面上研究了Cl+H2(D2)反应.所使用的两个势能面都是从CW(Capecchi和Wener)势能面得到的,第一个是CW势能面的基态面加自旋轨道耦合修正,第二个是CW势能面的基态面没有自旋轨道耦合修正.在这两个势能面上得到了碰撞能从0.1到1.4 eV的积分截面以及反应几率.对于Cl与D2反应,考虑自旋轨道耦合后由于势垒高度的增加反应截面向高能处有一个平移,但Cl与H2反应在低能处的反应活性反而增大了,原因是虽然自旋轨道耦合效应增加了势垒高度,同时减小了势垒宽度,隧道效应更加明显,而隧道效应在低能处起着比较重要的作用,所以反应活性比较大.当碰撞能大于0.7 eV时,没有考虑自旋轨道耦合时势垒高度较低,因而反应活性较大.  相似文献   

20.
将新型稀土配合物TbY(m-MBA)6(phen)2*2H2O掺杂到导电聚合物PVK中改善了配合物的成膜性和导电性, 作为发光层应用于有机电致发光. 分别制作了器件(1) ITO/PVKTbY(m-MBA)6(phen)2*2H2O/LiF/Al和以Alq为电子传输层的器件(2) ITO/PVKTbY(m-MBA)6(phen)2*2H2O/Alq/LiF/Al. 研究了两种器件的电致发光性能, 得到了最大效率为0.88 cd*A-1的器件. 研究了铽配合物与PVK共掺杂体系的激发光谱和光致发光谱, 发现两者之间存在着能量转移, 说明Y3+的存在促进了PVK到Tb3+的能量传递. 文章就器件的发光特性和掺杂体系的能量传递进行了初步讨论.  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