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Ionization and dissociation of nitrosyl chloride ClNO were studied using femtosecond laser mass spectra tech-nique.Strong fragmental ions NO~ and Cl~ were observed with the laser intensity varied from 3.2×10~(14) to 2.5×10~(15) W/cm~2.These fragmental ions were attributed to the direct dissociation of the parent ions.Electronic structurecalculations were also carried out with Hartree-Fock,density functional and correlated levels of theory to under-stand the possible fragmentation pathways.The very low N-Cl bond energy in the parent ion of nitrosyl chloride isa clear reason for the absence of ClNO~ and ClN~ ion peaks from the femtosecond laser mass spectrum. 相似文献
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CH2是燃烧和大气光化学中重要的自由基之一[1].在燃烧过程中,CH2自由基由碳氢化合物分子热解或由O原子和C2H2等反应生成.这种高活性的中间体,又可进一步与燃烧过程中其它重要物质如NOx(NO、NO2、N2O)发生反应.在低温燃烧过程中,N2O是NOx存在的主要形式,所以,研究CH2自由基与N2O的反应,对于了解燃烧机制有重要意义.就我们所知,关于CHZ和N20的反应,国内外还未见文献报导.本文从态-态反应的层次上,开展基电子态CH2(X3B1)自由基与N2O反应的实验研究.我们利用351um紫外激光光解CH2CO产生CH2自由基,这种方法… 相似文献
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The reaction dynamics of methylene radicalCH2((x)3B1)with N2O was investigated by Time Resolved Fourier Transform Infrared Spectroscopy(TR-FTIRS). Pure CH2((x)3B1) radical was produced via laser photolysis of ketene at 351 nm.. Nascent vibrationally excited products CO , NO and HCN were observed.. Some reaction pathways which may lead to these products were proposed and a possible reaction mechanism was outlined.. 相似文献
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We studied the ionization and dissociation of polyatomic molecule methane in an intense femtosecond laserfield with wavelength of 810 nm and intensities ranging from 1.4×10~(14)to 2.6×10~(15) W/cm~2 by massspeetroscopy.Abundant fragment inos were observed in addition to the strong parent ion.The effect offrequency chirp was investigated and it was found that the negatively chirped pulses dramatically enhancedthe dissociation probability,which might be used to control the dissociation pathways. 相似文献
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1999年 10月 12日 ,瑞典皇家科学院宣布将 1999年诺贝尔化学奖授予美国加州理工学院的物理化学和化学物理学家AhmedHZewail教授 ,以表彰他在利用飞秒激光脉冲技术研究化学反应方面的开拓性工作。图 1 AhmedHZewail教授 AhmedHZewail1946年 2月 2 6日生于埃及 ,至今仍然保留有埃及国籍。 1967毕业于埃及亚历山大大学 ,并于 1969年获得硕士学位。同年赴美国宾夕法尼亚大学化学系攻读博士学位。 1974年获博士学位后 ,他成为加州大学伯克利分校研究所的受IBM公司资助的博士后研究员。 1976年 ,他被… 相似文献
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In order to predict the field ionization probabilities, the accurate ab initio electrostatic potential of molecules has to be calculated. However, the calculation of the full ab initio electrostatic potential of molecules is complicated, even impossible for some larger molecules with low symmetry. Here, we present a semi-empirical model to treat the field ionization of molecules in an intense laser field. In this model, a modified Coulomb potential is used to take the place of the complicated ab initio electrostatic potential of molecules. The analytic equations of the Keldysh adiabatic parameter using the Coulomb potential and the modified Coulomb potential have first been given. Using our semi-empirical model, we have calculated the field ionization probabilities and the Keldysh adiabatic parameters of O2, N2, SO2, C2H4, CH3CN and C6H6 in an intense laser field. The results agree excellently with the calculations using the ab initio electrostatic potential of molecules. As the modified parameter for the Coulomb potential can be found from experimental measurements, the field ionization mechanism of molecules can be immediately predicted with our semi-empirical model. 相似文献
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强场下分子的电离与解离研究是一个新的研究领域 .分子内的分子实与价电子之间的库仑场强度为 108 V· cm- 1量级 .通常激光的电场强度远小于这个量级 ,因此可以采用微扰理论来解释分子在激光场中的电离与解离 .如果激光场的功率密度达到 1013 W· cm- 2以上 ,其电场强度就能到 8.7× 107 V· cm- 1以上 ,达到甚至超过分子内的电场强度 .此时微扰理论已经不太适用 ,分子的电离机理及研究方法将有所不同 [1- 5]. 关于强场电离与解离的理论没有统一的解释 [2,3].在强场下通常用 Keldysh因子γ来判断原子的电离方式 [6]:其中ω 0为激… 相似文献