缩胺基硫脲衍生物电子结构的HeI紫外光电子能谱研究

报道了一组具有生物活性的缩胺基硫脲衍生物电子结构的HeI紫外光电子能谱(PES)研究。PES谱的指认借助于对有类似原子基团的小分子的PES结果以及对每个研究分子的MNDO量子化学计算,同时由PES实验最低电离能(IP_s/eV)预指了该类衍生物间的相对生物活性大小,而研究分子最高占有轨道(HOMO)的π键属性促进了人们对这类衍生物生物活性的了解。     

B(OCH3)3电子结构的Hel紫外光电子能谱研究

人们知道，Hel紫外光电子能借（PES）提供研究分子轨道能量、能级次序、成键类型以及由光电子峰强度所反映的电离轨道特性等信息是其他手段没有的，因而PES技术已广泛地用于众多化合物分子电子结构的研究中．有机础化合物由于它们高的反应活性作为合成试剂而信受人们重视［‘－     

苯并噻唑衍生物的气相HeI紫外光电子能谱(UPS)及量子化学研究

对苯并噻唑系列衍生物的气相HeI紫外光电子能谱(UPS)进行了研究．首次报道 了五种化合物的紫外光电子能谱，利用Gaussian94从头算的量子化学计算方法对其 进行了计算，并结合计算结果对各个分子体系的谱图进行了指认．研究结果表明： 分子的电离能受取代基性质的影响，取代基的给电子能力越大，体系的共轭效应越 强，电离能就越低．对苯并噻唑衍生物而言，6-位取代基对电离能的影响大于2-位 取代基的影响．     

几种硫醚化合物的紫外光电子能谱及量子化学研究

报导了硫酸系列化合物DMS（二甲基硫酸），DpCPS（二对氯苯硫酸），DpTS（二对甲基苯硫醚）气相HcI紫外光电子能谱（UPs），其中DpCPS，DpTS的UPS谱为首次获得．对各体系利用MNDO方法进行了分子构型优化，对优化得到的优势构型实施RHF／6－31G量子化学计算，并利用计算结果对各个分子体系的UPS谱进行了指认，计算结果分析显示：a）S原子的孤对电厂在DpCPS和DpTS中起到阻碍形成遍及整个分子体系π轨道的阻断作用，故此不存在遍及整个分子体系的π轨道；b）通过对三体系第一电高能的对比分析表明，第一电高能所激发出的电子主要是受S原子的束缚；c）还得到另一个有意义的结论──各分子体系的第一电离能大小与HOMO中3Pz轨道所占成份成有很好的线性关系．表明体系的第一电离出的电子主要是受S原子的3Pz轨道束缚     

1,2,5-噻二唑衍生物电子结构的紫外光电子能谱研究

首次报导了１,２,５－噻二唑衍生物３－氯－１,２,５－噻二唑（Ａ）和３,４＝二氯－１,２,５－噻二唑（Ｂ）化合物的紫外光电子能谱（ＵＰＳ）,谱带的指认建筑在对谱带形状、相对强度、实验电离能（ＩＰＳ）的分析以对研究分子Ｇａｕｓｓｉａｎ ９４ＳＴ０－６Ｇ从头计算电离能（－ε１）。化合物Ｂ ＵＰＳ谱带的ＩＰＳ比相应的化合物Ａ的ＩＰＳ均你芝归结为Ｂ分子中两个取代Ｃ１原子上电子的拥挤效应。计算的Ｂ的 有量（     

ICl3电离能的实验和理论研究

结合紫外光电子能谱实验和量子化学计算方法研究了三氯化碘的电离能．实验得到的ICl3的紫外光电子能谱是一氯化碘和氯气的混合能谱,这表明ICl3分解为ICl和Cl2．采用B3LYlP方法在6-311 G(df)基组水平上得到了ICl3分解的过渡态．计算表明ICl3分解吸收少量热量,反应的活化能为168．4kJ／mol．采用HF方法和外壳层格林函数方法(OVGF)预测了ICl3不同轨道的电离能,OVGF方法得到的ICl3第一垂直电离能为10．372eV．     

BrCl紫外光电子能谱实验及理论研究

采用紫外光电子能谱研究了影响大气臭氧浓度的重要卤素互化物一氯化溴的精细电离能谱．实验得到BrCl的第一绝热电离能和垂直电离能分别为10．95eV和11．00eV．BrCl的最高占据轨道6π电离产生了明显的旋轨分裂谱带．这对旋轨分裂谱带分别清晰地显示出4个振动精细结构峰．频率分析显示BrCl分子最高占据轨道为弱反键性质．比较了HF方法和外壳层格林函数方法(OVGF)对电离能的计算结果,并对实验值进行了分析比较及指认．采用实验构型OVGF方法给出的电离能结果无论在低电离能区还是在高电离能区都和实验值一致,特别是第一垂直电离能10．988eV与实验值11．00eV非常好地吻合．     

苯氰基衍生物气相HeI紫外光电子能谱研究

气相Hel（21．22eV）紫外光电子能谱（UPS）能从孤立分子的分子轨道特性上，给出研究分子的轨道能量、电子结构以及成键特性的大量信息．UPS谱的特性揭示了被电离分子轨道的成键性质，而量子化学计算能正确地指认UPS谱带的归属，从而化合物的UPS研究从分子轨道的属性上提供了研究体系的实验和理论基础．苯基腈（C6H5CN）的UPS已有过研究［1-3］，但作为系列分子的间-二氰基苯（1）、对-二氰基苯（2）、1；2，4，5-四氰基苯（3）的HeI光电子能谱未见报道．这一系列分子的特点是-CN取代的数目和位置不同，通过这些分子UPS的研究找…     

同位素氧-18分子的He I紫外光电子能谱

HeⅠ photoelectron spectrum of isotopic 18O2 molecules has been firstly recorded on a double-chambers UPS machine Ⅱ which was built specifically to detect transient species. In comparison with UPS results of oxygen molecles 16O2 it is found that the reduction of adiabatic ionization potentials IPs, the decresae of vibrational intervals and the change of intensity of vibrational components on each ionic state of isotopic 18O2 molecules obviously appear on the UPS spectrum.     

SiBr~4及其不同离子态的电子结构研究: 紫外光 电子能谱(PES)和理论研究

本文详细报道了SiBr~4的紫外光电子能谱(PES)及该化合物不同离子态(X^2T~2,A^2T~1,B^2E,C^2T~2等)的电子结构和性质。实验测得对应基态离子态的绝热电离能I~a(X^2T~2←X^1A~1)=10.532eV,X^2T~2离子态的振动频率为(450±30)cm^-^1。结合理论计算对紫外光电子能谱进行了指认和分析,结果表明X^2T~2,A~2T~1两个离子态存在明显的自旋-轨道耦合作用,自旋-轨道耦合导致的分裂分别为：0.27ev和0.53eV。此外,不同计算方法比较显示外层格林函数方法计算得到电离能与实验吻合很好。     

Photoelectron Spectroscopy,Photoionization Mass Spectroscopy,and Theoretical Study on CCl3SSCN

Trichloromethanesulfenyl thiocyanate, CCl3SSCN, was generated and studied by photoelectron spectroscopy (PES), photoionization mass spectroscopy (PIMS), and theoretical calculations. This molecule exhibits a gauche conformation, and the torsional angle around S-S bond is 91.4 o due to the sulfur-sulfur lone pair interactions. After ionization, the ground-state cationic-radical form of CCl3SSCN*+ adopts a trans planar main-atom structure with Cs symmetry. The highest occupied molecular orbital (HOMO) of CCl3SSCN corresponds to the electrons mainly localized on the sulfur 3p lone pair MO. The first ionization energy is determined to be 10.40 eV.     

Theoretical study on the reaction mechanism of the methyl radical with nitrogen oxides

The radical-molecule reaction mechanism of CH3 with NOx (x = 1, 2) has been explored theoretically at the B3LYP/6-311Gd,p and MC-QCISD (single-point) levels of theory. For the singlet potential energy surface (PES) of the CH3 + NO2 reaction, it is found that the carbon to middle nitrogen attack between CH3 and NO2 can form energy-rich adduct a (H3CNO2) with no barrier followed by isomerization to b1 (CH3ONO-trans), which can easily convert to b2 (CH3ONO-cis). Subsequently, starting from b (b1, b2), the most feasible pathway is the direct N-O bond cleavage of b (b1, b2) leading to P1 (CH3O + NO) or the 1,3-H-shift and N-O bond rupture of b1 to form P2 (CH2O + HNO), both of which may have comparable contribution to the reaction CH3 + NO2. Much less competitively, b2 can take a concerted H-shift and N-O bond cleavage to form product P3 (CH2O + HON). Because the intermediates and transition states involved in the above three channels are all lower than the reactants in energy, the CH3 + NO2 reaction is expected to be rapid, as is consistent with the experimental measurement in quality. For the singlet PES of the CH3 + NO reaction, the major product is found to be P1 (HCN + H2O), whereas the minor products are P2 (HNCO + H2) and P3 (HNC +H2O). The CH3 + NO reaction is predicted to be only of significance at high temperatures because the transition states involved in the most feasible pathways lie almost above the reactants. Compared with the singlet pathways, the triplet pathways may have less contributions to both reactions. The present study may be helpful for further experimental investigation of the title reactions.     

Theoretical mechanistic study on the radical-molecule reaction of CHCl2/CCl3 with NO2

The radical-molecule reaction mechanism of CHCl(2) and CCl(3) with NO(2) have been explored theoretically at the B3LYP/6-311G(d,p) and MC-QCISD (single-point) levels. For the singlet potential energy surface (PES) of CHCl(2) + NO(2) reaction, the association of CHCl(2) with NO(2) was found to be a barrierless carbon-to-nitrogen approach forming an energy-rich adduct a (HCl(2)CNO(2)) followed by isomerization to b(1) (trans-cis-HCl(2)CONO), which can easily interconvert to b(2), b(3), and b(4). Subsequently, the most feasible pathway is the 1,3-chlorine migration associated with N-O1 bond cleavage of b(1) leading to P(1) (CHClO + ClNO). The second competitive pathway is the 1,4-chlorine migration along with N-O1 bond rupture of b(4) giving rise to P(2) (CHClO + ClON). Moreover, some of P(1) and P(2) can further dissociate to give P(6) (CHClO + Cl + NO). The lesser followed competitive channel is the 1,3-H-shift from C to N atom along with N-O1 bond rupture of b(1) to form P(3) (CCl(2)O + HNO). The concerted 1,4-H-shift accompanied by N-O1 bond fission of b(3) to product P(4) (CCl(2)O + HON) is even much less feasible. For the singlet PES of CCl(3) + NO(2) reaction, the only primary product is found to be P(1) (CCl(2)O + ClNO), which can lead to P(2) (CCl(2)O + Cl + NO) via dissociation of ClNO. The obtained major products CHClO and CCl(2)O for CHCl(2) + NO(2) and CCl(3) + NO(2) reactions, respectively, are in good agreement with kinetic detection in experiment. Compared with the singlet pathways, the triplet pathways may have less contributions to both reactions. Because the rate-determining transition state involved in the feasible pathways lie above the reactants R, the title reactions may be important in high-temperature processes. The similarities and discrepancies among the CH(n)Cl(3-n) + NO(2) (n == 0-2) reactions are discussed in terms of the substitution effect. The present study may be helpful for further experimental investigation of the title reactions.     

MoO_3电致变色薄膜的XPS研究

近年来 ,随着人们提倡节能和使用洁净能源 ,无机电致变色材料在建筑物采光控制系统和反射率可调表面的应用研究 ,已成为材料领域的一个新热点 .WO3、 MoO3等过渡金属氧化物薄膜具有良好的电致变色效应 ,是人们研究的重点 .其中 MoO3的电致变色效果要好于 IrO2、 TiOx、 CoO及 NiOx等电致变色材料 [1],而且它在可见光区有比 WO3更柔和的色彩 ,使人眼更易于适应其颜色变化 .着色态的 MoO3称为钼青铜 ,其开路记忆也好于钨青铜 [2].故 MoO3电致变色薄膜是极有潜力用于实用化的电致变色器件 .MoO3薄膜常用的制备方法有真空蒸 发、化学气…     

Theoretical study on the mechanism of the (3)CH(2) + NO(2) reaction

The complex doublet potential energy surface of the CH(2)NO(2) system is investigated at the B3LYP/6-31G(d,p) and QCISD(T)/6-311G(d,p) (single-point) levels to explore the possible reaction mechanism of the triplet CH(2) radical with NO(2). Forty minimum isomers and 92 transition states are located. For the most relevant reaction pathways, the high-level QCISD(T)/6-311 + G(2df,2p) calculations are performed at the B3LYP/6-31G(d,p) geometries to accurately determine the energetics. It is found that the top attack of the (3)CH(2) radical at the N-atom of NO(2) first forms the branched open-chain H(2)CNO(2) a with no barrier followed by ring closure to give the three-membered ring isomer cC(H(2))ON-O b that will almost barrierlessly dissociate to product P(1) H(2)CO + NO. The lesser followed competitive channel is the 1,3-H-shift of a to isomer HCN(O)OH c, which will take subsequent cis-trans conversion and dissociation to P(2) OH + HCNO. The direct O-extrusion of a to product P(3) (3)O + H(2)CNO is even much less feasible. Because the intermediates and transition states involved in the above three channels are all lower than the reactants in energy, the title reaction is expected to be rapid, as is consistent with the measured large rate constant at room temperature. Formation of the other very low-lying dissociation products such as NH(2) + CO(2), OH + HNCO and H(2)O + NCO seems unlikely due to kinetic hindrance. Moreover, the (3)CH(2) attack at the end-O of NO(2) is a barrier-consumed process, and thus may only be of significance at very high temperatures. The reaction of the singlet CH(2) with NO(2) is also briefly discussed. Our calculated results may assist in future laboratory identification of the products of the title reaction.     

Theoretical study on the mechanism of the 1CHCl + NO reaction

The complex doublet potential energy surface of the CHClNO system, including 31 minimum isomers and 84 transition states, is investigated at the QCISD(T)/6-311G(d, p)//B3LYP/6-31G(d, p) level in order to explore the possible reaction mechanism of the singlet CHCl with NO. Various possible isomerization and dissociation channels are probed. The initial association between 1CHCl and NO at the terminal N-site can almost barrierlessly lead to the chainlike adducts HClCNO a (a1, a2) followed by the direct Cl-extrusion to product P9 Cl + HCNO, which is the most feasible channel. Much less competitively, a (a1, a2) undergoes a ring-closure leading to the cyclic isomer c-C(HCl)NO d followed by a concerted Cl-shift and N-O cleavage of d to form the branched isomers ClNC(H)O f (f1, f2). Eventually, f (f1, f2) may take a direct H-extrusion to produce P7 H + ClNCO or a concerted 1,2-H-shift and Cl-extrusion to form P1 Cl + HNCO. The low-lying products P2 HCl + NCO, P3 Cl + HOCN, P14 HCO + 3NCl, P6 ClO + HCN, and P13 ClNC + OH may have the lowest yields observed. Our calculations show that the product distributions of the title reaction are quite different from those of the analogous 1CHF + NO reaction, yet are similar to those of another analogous 3CH2 + NO reaction. The similarities and discrepancies among the three reactions are discussed in terms of the substitution effect. The present article may assist in future experimental identification of the product distributions for the title reaction and may be helpful for understanding the halogenated carbene chemistry.