共查询到19条相似文献,搜索用时 828 毫秒
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利用分子束和化学发光技术,在单次碰撞条件下,首次研究了亚稳态原子He(23S)、Ne(3P0.2)与CH3NO2的解离激发反应,探测到反应的激发态产物(CH(A)、CH(B)、CH(C)的化学发光,在He(23S)/CH3NO2反应中同时探测到H(Balmer)的发射.利用He(23S)+N2→N2+(B)+He+e-作参考反应,测定了反应He(23S)/CH3NO2产生的CH的A-X,B-X,C-X以及H原子的发射速率常数.利用化学发光光谱的计算机模拟,求得了激发态产物CH(A)的初生态振动布居和转动温度.结合相空间理论对解离过程CH(A)的形成通道进行了讨论,认为CH(A)的形成是经由中间体CH3*的二体解离过程. 相似文献
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在分子束条件下利用化学发光技术研究了亚稳态惰性气体原子He(23S1)和Ne(3P0,2)与NH3碰撞的解离激发反应.He(23S1)与NH3的反应中观察到NH(A-X,c-a,c-b),NH+(B-X)和H*-Balmer发射.对NH(A-X,c-a)的谱图进行了拟合.分析NH(c-b)谱发现NH(c)倾向于生成具有f对称性的转动能级,NH3可能是经由一个NH2中间体分两步解离,这与121.6nm光解NH3时的倾向性正好相反.利用参比反应测得生成NH(A,c)的速度为k=1.0×10-11cm3•s-1.He(23S1)与NH3生成的NH(A,v’=1)的转动激发比v’=0时要高,根据含角动量守恒的相空间理论,其生成过程可能具有较大的解离半碰撞参数.Ne(3P0,2)与NH3反应只有NH(A-X,c-a)发射,NH(A,c)的振转布居可由简单相空间理论三体解离模式解释. 相似文献
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CH4+O(3P)→CH3+OH反应的准经典轨线研究 总被引:1,自引:0,他引:1
用准经典轨线方法研究了O(3P)与CH4的反应,计算结果表明,CH4(υ=0,j=0)与O(3P)的反应在低及高的碰撞参数下都是直接反应,无短寿命的碰撞复合物生成,产物OH以向后散射为主,基本上处于振转基态.CH4(υ=1,j=1)与O(3P)的反应在低及高的碰撞参数下反应机理不一样。在低碰撞参数下是直接反应,无短寿命的碰撞复合物生成,产物OH以向后散射为主,主要处于振动基态,转动基本上是冷的,但比高碰撞参数下的热.在高的碰撞参数下则生成短寿命的碰撞复合物,产物OH以向前散射为主,表现出明显的周边动力学反应的特征,主要处于振动激发态(υ=1),但转动仍然是较冷的。 相似文献
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利用流动余辉技术研究了亚稳态氦与CHBr_3、CH_2Br_2的传能反应。由激发态碎片的发射光谱测定了CH(A,B,C)等碎片的相对布居、形成速率常数和CH(A~2Δ,v'=0)的转动温度,并对传能反应机理进行了初步的讨论。 相似文献
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质子键合的分子簇的离子-分子反应中的热化学和动力学关系的考察结果表明:对于非烷基锁闭的分子簇,如(C2H5OH)nH+(5=1-3)和(CH3OH)3H+;与中性碱B的质子转移反应,属快速反应,其反应效率r是由总反应的自由能变化△γGm控制,而与反应过渡态的本质无关。那些反应可能存在两个中间体,因电子转移导致质子从分子簇内部转移到中性碱,进而导致二个或三个溶剂分子的直接蒸发;烷基锁闭的质子键合的二聚体,如(CH3CN)2H+,(CH3OCH3)2H+,(CH3COCH3)2H+和(C3COOCH3)2H+,与中性碱的质子转移反应,其效率远小于1;与总反应的△γGm无关 相似文献
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锌卟啉配合物轴配反应的光谱及电子效应 总被引:1,自引:0,他引:1
用紫外-可见分光光度计研究了三种新型空间不对称金属席夫碱和四种取代咪唑与间位取代四苯基卟啉锌(ZnT(m-X)PP,X=NO2,Cl,OCH3,H,CH3)在CH2Cl2中的轴向配位反应的紫外-可见吸收光谱,发现在450-700nm间存在等吸光点;采用Rose-Drago数据处理方法确定了各体系在25℃时平衡常数,发现所研究的35个配位反应体系的配位数均为1,各配体与锌卟啉配位反应的εβ/εα及平衡常数均分别与卟啉环上取代基的Hammett参数间存在线性自由能关系. 相似文献
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用量化学UMP2方法,在6-311++G**基组水平上研究了CH_2X(X=H,FCI)与臭氧反 应机理,全参数优化了反应过程中反应物、中间体、过渡态和产物的内何构型,在 UQCISD(T)/6-311++G**水平上计算了它们的能量,并对它们进行了振动分析,以 确定中间体和过渡态的直实性。从CH_2X(X=H,FCI)与O_3的反应机理的研究结果看 ,它们与O_3反应的活性都比较强,相对而言,活性大小顺序为CH_2F>CH_3> CH_2CI,也就是说,CH_2F自由基与臭氧间的反应活性最强,对大气臭氧的损耗将 是最大的。同时研究还发现CH_2X(X=H,FCI)系列自由基与O_3的反应都是强放热反 应。 相似文献
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The excited fragments CH(A), CH(B), CH(C) etc. were produced by the bombardment of He(2~3S) with CH_nX_(4-n)(X=Cl, Br, I). Based on the CH(A-X) emission spectra, the rotational populations can be interpretated in terms of Boltzmann distribution. The effective rotational temperature for CH(A,v'=0) produced from various methyl halides are nearly the some. Experiments under various pressure and calculation of collisional dynamics showed that the distributions are approximate to the nascent distributions. 相似文献
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The photoionization spectroscopy of Si(CH3)3Cl in the range of 50 -130 nm was studied with synchrotron radiation source. The adiabatic ionization potentials of molecule Si(CH3)3Cl and radical Si(CH3)3 are 10.06 ±0.02 eV and 7.00±0.03 eV respectively. In addition, the appearance potentials of Si(CH3)2Cl+, Si(CH3)3+, SiCl+ and SiCH3+ were determined:
AP(Si(CH3)2Cl+) =10.49±0.02eV, AP(Si(CH3)3+) = 11.91 ±0.02eV
AP(SiCl+) = 18.64 ±0.06eV, AP(SiCH3+)= 18.62 ±0.02eV
From these, some chemical bond energies of Si(CH3)3Cl+ were calculated:
D(Si(CH3)2Cl+ - CH3) =0.43 ±0.02eV, D(Si(CH3)3+ - Cl) = 1.85 ± 0.02eV
D(SiCH3+ - (2CH3 + Cl)) = 8.56 ± 0.06eV, D(SiCH3+ - 2CH3) =6.71±0.06eV
D(SiCl+ - 3CH3) = 8.58 ± 0.06eV, D(SiCl+- 2CH3) = 8.15 ±0.06eV
D(SiCH3+- (CH3 + Cl)) =8.13 ±0.06eV 相似文献
AP(Si(CH3)2Cl+) =10.49±0.02eV, AP(Si(CH3)3+) = 11.91 ±0.02eV
AP(SiCl+) = 18.64 ±0.06eV, AP(SiCH3+)= 18.62 ±0.02eV
From these, some chemical bond energies of Si(CH3)3Cl+ were calculated:
D(Si(CH3)2Cl+ - CH3) =0.43 ±0.02eV, D(Si(CH3)3+ - Cl) = 1.85 ± 0.02eV
D(SiCH3+ - (2CH3 + Cl)) = 8.56 ± 0.06eV, D(SiCH3+ - 2CH3) =6.71±0.06eV
D(SiCl+ - 3CH3) = 8.58 ± 0.06eV, D(SiCl+- 2CH3) = 8.15 ±0.06eV
D(SiCH3+- (CH3 + Cl)) =8.13 ±0.06eV 相似文献
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在B3LYP/6-311 G(2df,p)的水平上,对反应X- CH3SCl(X=F,Cl,Br,I)进行了理论研究.计算结果表明:X-(X=Cl,Br,I)与CH3SCl作用时,实际发生的是在硫原子上而不是在碳原子上的亲核取代反应,而且属于加成-消去机理.但是F-与CH3SCl作用则容易发生脱质子反应. 相似文献
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The dissociation dynamics of He...I 35Cl(B,v'=2,3) complexes with varying amounts of internal energy
The He...I (35)Cl intermolecular vibrational levels with n'=0-6 that are bound within the He+ICl(B,v'=3) potential [A. B. McCoy, J. P. Darr, D. S. Boucher, P. R. Winter, M. D. Bradke, and R. A. Loomis, J. Chem. Phys. 120, 2677 (2004)] are identified in laser-induced fluorescence experiments performed at very low temperatures within a supersonic expansion. Comparisons of the positions and intensities of these lines with the excitation spectra, calculated using potential surfaces to describe the interactions between the helium atom and ICl in its ground and excited state, assist in the assignments. Based on these comparisons the excited state potential was rescaled so that the experimental and calculated J'=0 energies agree to within the experimental uncertainties for all but the lowest, n'=0, intermolecular level. Two-laser, action, and pump-probe spectroscopy experiments indicate that the bound He...I (35)Cl(B,v'=3) intermolecular vibrational levels undergo vibrational predissociation forming rotationally excited I (35)Cl(B,v'=2,j') products with distributions that depend upon the initial intermolecular vibrational level excited. Action spectra recorded in the ICl B-X, 2-0 region while monitoring the Deltav=0, I (35)Cl(B,v'=2) channel reveal two additional dissociation mechanisms for the He...I (35)Cl(B,v') excited state complexes: rotational predissociation of discrete metastable states lying slightly above the He+I (35)Cl(B,v'=2) asymptote and direct dissociation that occurs when the linear conformer is excited to the continuum of states above the same asymptote. The rotational predissociation pathway forms I (35)Cl(B,v'=2,j') products in all of the rotational states energetically accessible. The direct dissociation mechanism yields very cold rotational product state distributions; for instance, the average rotational energy in the product state distribution measured when the linear complexes are prepared 20 cm(-1) above the dissociation limit is only 1.51 cm(-1), representing only 7.6% of the available energy. 相似文献
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Darr JP Crowther AC Loomis RA Ray SE McCoy AB 《The journal of physical chemistry. A》2007,111(51):13387-13396
The dependence of the long-range interactions between molecular hydrogen and iodine monochloride on the geometry between the molecules is investigated. Laser-induced fluorescence and action spectroscopy experiments have identified multiple conformers of the o,p-H2...I35,37Cl(X,v' '=0) van der Waals complexes. A conformer with the hydrogen molecule localized at the iodine end of the dihalogen, most likely with C2v symmetry, is significantly more stable than an asymmetric conformer with the hydrogen localized in the well oriented orthogonally to the I-Cl bond axis, D0' ' = 186.4(3) cm-1 versus 82.8(3) 相似文献
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运用量子化学密度泛函理论UB3LYP/6-311+G*和高级电子相关校正的偶合簇(CCSD(T)/6-311+G*)方法,对CH3CH2,CH3CHCl和CH3CCl2自由基与NO2反应的机理和动力学进行了理论研究,得到了体系的势能面信息和可能的反应机理.根据计算得到的各反应热力学参数及反应能垒,采用传统过渡态理论计算了各反应在温度T=298 K和T=700 K时的速率常数.研究结果表明,该类反应均通过1个中间体和1个过渡态生成产物,产物分别为CH3CHO+HNO,CH3CHO+ClNO和CH3CClO+ClNO. 相似文献