势能面拓扑结构失稳与A+B2反应途径分叉条件

研究势能面拓扑结构对认识势能面的复杂性，分析势能面的关键区域，简化量化计算以及了解反应机理等都具有极其重要的意义＊．近些年来，关于势能面反应途径分又研究表明：势能面拓扑结构失稳会导致反应途径分叉，从而使得分子体系出现一系列新的现象和规律［’－’］．根本上来说，势能面拓扑结构最终由临界点的拓扑性质以及其数目所决定［‘1．因而研究势能面临界点的种类及其变化有至关重要的作用·本文用微分动力学系统定性方法分析了势能面上临界点的拓扑结构类型，并给出平面线性线系统势能面拓扑结构失稳的条件；针对三原子A＋BZ反…     

复盐K2Mg(IO3)4 2H2O的热力学性质

由于碱金属碘酸盐晶体在电学性质的利用上有重要价值和发现碘酸盐晶体非线性性质［‘］，七十年代以来，Vinogradov等对碘酸盐-碘酸-水系统发生了极大的兴趣，做了大量研究工作［’－‘］，发现在碘酸盐．碘酸一水三元体系里有碘酸盐复盐K2M（IO3）4·2H2O（M＝Mn2＋、Co2＋、N     

370-410nm波段CS2的共振多光子电离研究

对CS。人们曾做过广泛的研究，其中光谱研究以吸收谱最多，CSZ的解离动力学的研究也比较多．Butler等［‘］用193urn激光单光子激发CSZ获得CS碎片，研究了CSZ的解离．Seaver等［’1分别用266DD和193。激光多光子电离CSZ．但他们都是在固定激发波长下研究CSZ的解离．在370－405u     

EXAFS研究合成甲醇催化剂Cu／ZnO／MxOy

有关CO。＋H。合成甲醇催化剂的研究已有许多报道［‘－’j，但目前对活性中心及反应机理的认识仍不～致，其中对活性中心的看法归纳起来有3种：（1）Cll为活性中心“‘；（2）Cll”为活性中心［’j；（3）Cll－CtJ”为活性中心［‘1．研究发现，第三组分（如AI刀。）的加入可防止Cu粒子的烧结［’］，使Cu产生无序及缺陷结构，有利于CO。的吸附、活化［‘j及起到高分散Cu／Zno的稳定剂的作用［’j．由于三组分催化剂结构的多相性和准非晶态性，通常的XRD方法难以明确了解其结构，而EXAFS方法对研究局部有序结构特别有效．本文以Z…     

硫脲与多种阴离子共吸附行为的拉曼光谱研究

在电化学的研究与应用中，因硫豚（1’川可用作电镀添加剂、金属的缓蚀剂和一些电极反应的催化剂［‘］而受到人们的广泛重视．早在三十年代初就开展了有关水溶液和非水溶液体系中硫豚在不同金属电极表面的吸附行为的研究【’，’］、随着光谱电化学技术的建立、发展和不断完善     

双核Cu(Ⅰ)配合物的热分解非等温动力学

由于钢作为活性配位中心离子，存在干具有生物功能的蛋白质大分子中，近年来钢的配位化学受到广泛关注．普遍认为，咪唤基在铜蛋白的配位化学中起重要作用＊，开展钢与具咪陵基配体所形成配合物的研究，有助于揭示钢在蛋白质中的生物化学功能及其与咪哩基等其它基团相互键合作用的本质．我们曾报导了四种新型具苯并咪吐基双核CIJ（）配合物：［CllZ’（OCTB）flC104h·1．SHZO川，［Cll。’（NMOCTB）］·（CIO。）。·H。O（2），［Cll。’（NBUOCTB）］（CIO。）z切，［Cll。’（NBOCTB）］·（CIO4h·H。O（4）的合…     

Pb_n(n=2～30)团簇结构及铅晶体表面过程的计算机模拟

本文作者近年来采用 Ｍｕｒｒｅｌｌ等提出的有效的二体加三体展开势能函数（ｅｆｆｅｃｔｉｖｅｔｗｏ－ｐｌｕｓ－ｔｈｒｅｅ－ｂｏｄｙ ｐｏｔｅｎｔｉａｌ ｅｎｅｒｇｙ ｆｕｎｃｔｉｏｎ）研究过 Ｓｉｎ［１］、Ｇｅｎ［２］及 Ｘｎ［３］（Ｘ＝Ｌｉ,Ｎａ,Ｋ等）等微团簇的结构和相对稳定性,并提出笼状锗结构预测［４］。本文试图将这一具有简单解析形式的势能函数模型推广到Ｐｂｎ团簇及面心立方晶体铅表面过程的计算机模拟。对Ｐｂｎ这样的重金属团簇,从头计算结果还仅限于 Ｐｂ２、Ｐｂ３和 Ｐｂ４,实验中观察到 Ｐｂ７结构中…     

O／W微乳液中聚邻甲苯胺超微粒子的制备

聚邻甲苯胺具有较高的电导率、较好的贮存电荷的能力和良好的环境稳定性，因而具有较大的应用价值［’－‘j，其合成方法主要有电化学合成法和化学合成法［‘·’J．化学会成法所得聚邻甲苯肢的粒子一般大于100urn．近年来，以表面活性剂聚集体微乳液、溶致液晶为介质，制备超微粒子材料已为人们所关注「’－’］．以微乳液为介质进行聚合反应亦引起重视，但大部分微乳液聚合都是在四组分微乳液（表面活性剂、助表面活性剂、单体和水）中进行‘”·“‘．近年来，某些油溶性单体已成功地在无助表面活性剂的三组分微乳液中聚合［‘’·‘’1…     

邻乙酰基环酮热分解反应的理论研究

酸基化合物是一类极为重要的有机物,早在三十年代末,Hard等人就对式（1）所示的反应进行了实验研究问．近几十年来,这类化合物气相热分解反应的实验研究常有报导t’－7］,并且指出式（1）是途经六元环过渡态的单分子反应．为了配合实验工作,我们曾对酸氧基甲酸酯同、二乙酸亚胺和硫代乙酸胺的反应机理做过理论研究,并作了报导同．本文用PM3方法［‘’］研究邻乙酸基环戊酮和邻乙酸基环已酿的气相热分解反应,力图得到比此两种目标反应的实验研究［“］结果更详细的信息．h十算细节研究过程中,对平衡几何构型用能量梯度法全优化;对…     

对硝基甲苯的同步辐射光电离研究

光电离对硝基甲苯（PNT）可获得其电离势及碎片离子的出现势，并由此推断出离子产生的可能通道．目前尚未见到有关PNT光电离研究的报道，仅George等［‘j使用电子轰击电离质谱测得过它的电离势．我们使用同步辐射光电离质谱测得了PNT的电离势和8种碎片离子的出现势，给出了飞行时间（TOF）质谱图，归属了质谱中的主要离子峰，初步分析了光解离电离通道．1实验部分实验装置由阈值光电子一光离子符合（TPEPICO）装置改造而成［’，’］，光电离室上方的四极质谱计由TOF质谱计代替，下方的四极质谱计由盛固体样品的小炉取代．样品蒸…     

An SCF-CI method for determining the potential energy surface of a triatomic molecule

A self-consistent-field (SCF)-configuration interaction (CI) (SCF-CI) method for determining the potential energy surface of a triatomic molecule from the observed vibrational band origins has been suggested. By this method, the SCF-CI procedure in the internal coordinates is used to calculate the vibrational bond origins and their first derivatives with respect to parameters in the potential energy function using the exact vibrational Hamiltonian, and the optimizer LMF in the nonlinear-squares problem is employed to optimize parameters in the potential energy function. This approach is used to optimize the potential energy function of the water molecule. The standard deviation of this fitting to the 70 observed band origins is 1.154cm-1.     

OCS电子基态势能面与振动光谱的理论研究

本文采用键长-键角内标系下的自洽场-组态相互作用方法精确计算了OCS分子的振动高激发态能级,并结合实验观测到的振动能级利用非线性最小二乘法优化电子基态势能函数中的势能参数。由优化所得的势能面计算出的振动激发态能级与50个实验观测到的振动能级比较,标准偏差为0.08cm^-^1。此外,还用该势能面计算了OCS同位素分子的振动能级,计算结果与实验值也十分吻合。     

SO2基态势能面和振转能级的理论研究

在键长-键角坐标下,精确求解SO₂的核振动方程,并通过与实验数据比较来优化势能参数,由所得势能面计算得到38个振动能级,与实验值相比,均方根误差为0.93cm^-1.计算了³⁴SO₂的部分振动能级以及³²SO₂的J=6以下的部分振动能级,所得结果均与实验值较为吻合     

H2SiCl2分子Si-H振动"基座"SiCl2的有效质量

用傅立叶变换光谱仪和激光腔内吸收光谱仪记录了H2SiCl2分子2000～9000和12000～12900 cm-1的红外吸收光谱.依据局域模理论的非谐性耦合非谐振子(ACAO)模型,分析并拟合了Si-H的对称伸缩振动和反对称伸缩振动,得到描述Si-H伸缩振动的Morse离解能De 、 Morse振子参数α和键振子势能耦合系数frr′.分析中忽略了SiCl2"基座"对Si-H伸缩振动的影响,拟合结果与实验值符合的很好,拟合方差小于 1 cm-1,表明这一近似是可取的.分析拟合结果表明, Si-H振动时"基座"SiCl2的有效质量为75.     

Infrared spectrum of 4-methoxypicolinic acid N-oxide: computation of asymmetric O-H stretching band

In this article we studied the strong intramolecularly hydrogen-bonded system 4-methoxypicolinic acid N-oxide. The potential energy surface V = V(rOH,rOO) and the corresponding dipole moment function were calculated using the DFT B3LYP/6-31+G(d,p) level of approximation. The time-independent vibrational Schr?dinger equation was solved using a rectangular grid basis set and shifted Gaussian basis set. The vibrational spectrum and metric parameters were also calculated. Effects of deuteration were considered. The calculated vibrational spectra were compared with the experimental spectra. The vibrational transition corresponding to asymmetric O-H stretching that occurs at about 1400 cm-1 compares well with the experimentally assigned O-H asymmetric stretching band centered at 1380 cm-1. The corresponding asymmetric O-D stretching band was predicted to be at 1154 cm-1, while the experimental O-D band was not assigned due to its very low intensity. Several overtones and hot transitions of significant intensities were located in the vicinity of the fundamental O-H stretching frequency, effectively broadening the infrared absorption attributed to the O-H stretching mode. This is in a good agreement with the observed broad protonic absorptions found in the infrared spectra of the title compound and its analogs. We have shown that the Gaussian basis set is the method of choice for a two-dimensional vibrational problem that requires several hundreds of vibrational basis functions and when high accuracy of the eigenvalues is required or when extending the calculations to more vibrational degrees of freedom. We have also demonstrated that for a large number of basis functions the Gramm-Schmidt orthogonalization procedure outperforms symmetric and canonical orthogonalization schemes.     

塞曼效应在Cl2+及其同位素分子离子光谱标识中的应用

The A2Πu-X2Πg electronic absorption spectrum of the Cl2+ molecular cation in the region between 16820 and 17350 cm-1 was observed by employing optical heterodyne magnetic rotation enhanced velocity modulation spectroscopy. Cl2+ is a paramagnetic molecule; however, the intensities of some spectral lines, belonging to three bands whose origins are near 17282, 17324 and 16913 cm-1, respectively, remain unchanged with in the magnetic field. This indicates that both the upper and lower states have a weak Zeeman effect. The Zeeman contribution is nearly zero for the 2Π1/2 state, while nonvanishing for the 2Π3/2 state. Therefore, this behavior for the spectral assignment of Cl2+, including its isotopics was utilized and the identity of these bands was confirmed as members of the Ω=1/2 component of the electronic transition conveniently and unambiguously. The assigned bands are the (3, 7) band of the Ω=1/2 component of 35Cl+2 and 35Cl37Cl+ and the (2, 7) band of the Ω=1/2 component of 35Cl2+. It extends the range of vibrational assignments considerably in both the ground and the excited state, and leads to the successful rotational analysis. New molecular constants of Cl2+ were obtained from the observed line positions, band by band, using a weighted least squares fitting procedure.     

Theoretical studies on the potential energy surface and rovibrational states for the electronic ground state of carbonyl sulfide

A potential energy surface for the electronic ground state of carbonyl sulfide was optimized by using a self-consistent field-configuration interaction method and involving the recent observed vibrational band origins up to 8000 cm⁻¹ for the Σ state. The root mean square error for this refinement was found to be 0.27 cm⁻¹. The calculated quartic force constants from the refined potential are very close to the recent high level ab initio calculations. The vibrational energy levels for the Π and Δ states and for some isotopomers of carbonyl sulfide molecule were calculated to test the refined potential. The calculated energy levels are in good agreement with the experimental values.     

1-萘酚的紫外共振双光子电离光谱

利用脉冲分子束技术, 在305-322 nm范围内研究了1-萘酚(1NP)的共振双光子电离(R2PI)光谱. 1NP分子存在cis和trans两种旋转异构体, 但实验中仅观测到trans异构体的电子振动跃迁光谱, 其S1←S0跃迁的(0-0)带头出现在317.90 nm(即31456 cm-1)位置. 利用光谱选律及ab initio和密度泛函(DFT)计算, 对trans异构体在S1态的振动模进行标识, 得出主要对应于对称性为a'的平面内振动模. 计算显示, cis异构体在电子基态S0的能量较trans异构体高出439 cm-1, 而第一激发能却比trans异构体的低1216 cm-1, 与之相应的实验值分别是220和274 cm-1. 计算数值与实验结果在能量变化趋势上完全一致. 共振双光子电离谱中没有观测到cis异构体的光谱信号, 其原因可归结为分子束的有效冷却效应使得处于基态的cis异构体的布居数密度相对trans异构体极低, 导致cis光谱信号太小而未能被探测到.     

The vibration-rotation emission spectrum of hot BeF2

The high-resolution infrared emission spectrum of BeF2 vapor at 1000 degrees C was rotationally analyzed with the assistance of large-scale ab initio calculations using the coupled-cluster method including single and double excitations and perturbative inclusion of triple excitations, in conjunction with correlation-consistent basis sets up to quintuple-zeta quality. The nu3 fundamental band, the nu1+nu2, nu1+nu3, and 2nu2+nu3 combination bands, and 18 hot bands were assigned. The symmetric stretching (nu1), bending (nu2), and antisymmetric stretching (nu3) mode frequencies were determined to be 769.0943(2), 342.6145(3), and 1555.0480(1) cm-1, respectively, from the band origins of the nu3, nu1+nu3, and nu1+nu2 bands. The observed vibrational term values and B rotational constants were fitted simultaneously to an effective Hamiltonian model with Fermi resonance taken into account, and deperturbed equilibrium vibrational and rotational constants were obtained for BeF2. The equilibrium rotational constant (Be) was determined to be 0.235 354(41) cm-1, and the associated equilibrium bond distance (re) is 1.3730(1) A. The results of our ab initio calculations are in remarkably good agreement with those of our experiment, and the calculated value was 1.374 A for the equilibrium bond distance (re). As in the isoelectronic CO2 molecule, the Fermi resonance in BeF2 is very strong, and the interaction constant k122 was found to be 90.20(4) cm-1.     

利用真空紫外脉冲场电离-光电子方法研究三氯乙烯阳离子振动光谱

The vacuum ultraviolet（VUV）pulsed field ionization-photoelectron（ PFI-PE）spectrum for trichloroethene（ClCH=CCl2）has been measured in the energy range of 76400-79650 cm-1 . The vibrational bands resolved in the VUV-PFI-PE spectrum are assigned based on ab initio vibrational frequencies and calculated Franck-Condon factors for the ionization transitions,yielding eleven vibrational frequencies for ClCH=CCl2+:v1+=148 cm-1,v2+= 80 cm-1,v3+=286 cm-1,v4+=402 cm-1,v5+= 472 cm-1,v6+=660 cm-1,v7+=875 cm-1,v8+=990 cm-1,v9+=1038 cm-1,v10+=1267 cm-1,and v11+=1408 cm-1. These measurements along with the frequency v12+=3073 cm-1 determined in the recent VUV-infrared photo-induced ionization study have provided the complete set of twelve experimental vibrational frequencies for ClCH = CCl2+ in its ground electronic state. On the basis of the spectral simulation of the origin VUV-PFI-PE vibrational band,we have determined the IE（ClCH=CCl2）to be（76441.7±2.0）cm-1（（9.4776±0.0002）eV）.