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1.
The Ne* (3P2) Penning electron spectra and the Ne I photoelectron spectra of ethylene, benzene, 1,3-butadiene, and styrene were compared. The π bands in the Penning spectra showed enhancement relative to the σ bands in comparison with the corresponding photoelectron spectra, suggesting that Penning electron spectroscopy has potential value for the assignment of photoelectron bands. 相似文献
2.
Kishimoto N Hagihara Y Ohno K Knippenberg S François JP Deleuze MS 《The journal of physical chemistry. A》2005,109(46):10535-10546
We report on the results of an exhaustive study of the interplay between the valence electronic structure, the topology and reactivity of orbitals, and the molecular structure of biphenyl by means of Penning ionization electron spectroscopy in the gas phase upon collision with metastable He*(2(3)S) atoms. The measurements are compared with one-particle Green's function calculations of one-electron and shake-up valence ionization spectra employing the third-order algebraic diagrammatic construction scheme [ADC(3)]. Penning ionization intensities are also analyzed by means of the exterior electron-density model and comparison with photoelectron spectra: in contrast with the lines originating from sigma orbitals, ionization lines belonging to the pi-band system have large Penning ionization cross sections due to their greater extent outside the molecular van der Waals surface. The involved chemi-ionization processes are further experimentally investigated using collision-energy-resolved Penning ionization electron spectroscopy. The cross sections of pi-ionization bands exhibit a markedly negative collision-energy dependence and indicate that the interaction potential that prevails between the molecule and the He*(2(3)S) atom is strongly attractive in the pi-orbital region. On the other hand, the partial ionization cross sections pertaining to sigma-ionization channels are characterized by more limited collision-energy dependencies, as a consequence of rather repulsive interactions within the sigma-orbital region. A comparison of ADC(3) simulations with the Penning ionization electron spectra and UV photoelectron spectra measured by Kubota et al. [Chem. Phys. Lett. 1980, 74, 409] on thin films of biphenyl deposited at 170 and 109 K on copper demonstrates that biphenyl molecules lying at the surface of polycrystalline layers adopt predominantly a planar configuration, whereas within an amorphous sample most molecules have twisted structures similar to those prevailing in the gas phase. 相似文献
3.
Toshiaki Munakata Koichi Ohno Yoshiya Harada Kozo Kuchitsu 《Chemical physics letters》1981,83(2):243-245
The Ne1(3P2) Penning electron spectra and the Ne I photoelectron spectra were measured in the gas phase. The observed systematic differences in their relative intensities were interpreted in terms of the electron distributions of the relevant molecular orbitals and used for assignment of the deep π bands, π1 (12.4 eV) for naphthalene, and π2 (11.9 eV) and π1 (12.8 eV) for anthracene. 相似文献
4.
《Spectrochimica Acta Part B: Atomic Spectroscopy》2006,61(6):660-673
The occurrence of charge transfer and Penning process in glow discharge atomic emission sources can have a profound effect on the specific and overall spectral emission line characteristics of analyte species in these sources. A detailed spectral illustration of several of these effects is presented in this study for Cu, Zn, Ag and Cd with a particular focus on the ionic emission characteristics (i.e. II lines) of these elements. Charge transfer and Penning processes in glow discharge devices are driven by ionic and metastable species generated from the filler gas. Comparison of spectra obtained utilizing different filler gases is particularly effective for revealing the unique and specific excitation pathways for the analyte ions. Detailed high resolution spectra are presented and compared for Cu and Zn (brass) with Ar, Ne or He filler gases and for Ag and Cd with Ar or He as the filler gas illustrating several charge transfer and Penning processes. Unambiguous identification of spectral lines for specific transitions was facilitated by the acquisition of all spectral data utilizing a UV–visible Fourier transform spectrometer. This spectrometer provided complete and continuous coverage of the spectral region from 200 to 650 nm and allowed spectral lines to be identified with an accuracy of 1–2 pm. 相似文献
5.
Energy distributions of electrons emitted from polycrystalline naphthacene due to the impact of metastable argon or krypton atoms were measured. The energy distribution peaks, except for large peaks appearing near zero eV, correspond to the kinetic energies estimated from photoelectron spectra on the assumption that the excitation energies of the metastable atoms are transferred to the electrons in the valence bands. The results are interpreted as the occurrence of Penning ionization (Auger de-excitation) on the naphthacene surface. 相似文献
6.
7.
Wang CC Kornilov O Gessner O Kim JH Peterka DS Neumark DM 《The journal of physical chemistry. A》2008,112(39):9356-9365
Helium droplets doped with Xe and Kr atoms were photoionized by using VUV synchrotron radiation from the Advanced Light Source and the resulting photoelectron images were measured. A wide range of He droplet sizes, photon energies, and dopant pick-up conditions was investigated. Significant ionization of dopants was observed at 21.6 eV, the absorption maximum of 2p (1)P1 electronic excited state of He droplets, indicating an indirect ionization mechanism via excitation transfer. The photoelectron images and spectra reveal multiple photoionization mechanisms and pathways for the photoelectrons to escape the droplet. Specifically, they show sets of sharp peaks assigned to two mechanisms for Penning ionization of the dopant by He* in which the photoelectrons leave the droplet with no detectable energy loss, a broad, intense feature representing electrons that undergo significant energy loss, and a small amount of ultraslow electrons that may result from electron trapping at the droplet surface. The droplet-size dependence of the broad, intense feature suggests the development of the conduction band edge in the largest droplets seen here ((N) approximately 250,000). 相似文献
8.
The UV photoelectron spectra of simple members of the 1H- and 2H-triazaphospholes are reported; the spectra were assigned by ab initio molecular-orbital configuration-interaction methods, following the observation of breakdown of Koopmanns' theorem at the SCF level. The ring electron distribution, and the implications for reactivity of the rings are discussed. 相似文献
9.
硫氧化碳OCS是线性三原子分子,这类小分子的激发态、离子态能级结构、能级之间的相互作用及电离过程,是研究中所关心的问题.Tanaka等[1]和Kopp[2]测量了OCS的VUV吸收光谱,Frey和Schlag等[3]以同步辐射光源,用光电离共振(PIR)谱方法、Kovac[4]和Wang,Shirley等[5]以Hel为电离光源,分别采用传统的光电子能谱和高分辨光电子能谱技术研究了CO2、CS2和OCS分子从电子振动基态吸收单个光子而电离的过程.Yang和Anderson等问为了作选态的离子一分子反应利用可调谐激光rt光子吸收将OCS选择激发到某一中间态,OCS再吸收光子后… 相似文献
10.
Valence-band angle-resolved photoelectron spectra of oriented polycrystalline films of hexatriacontane (n-C36H74) were measured by He II (40.8 cV) light. Significant dependence of the spectra on photoemissive angle and light-incidence angle was observed. The advantages and problems of angle-resolved UV photoelectron spectroscopy to the study of electronic structures of organic crystals are discussed. 相似文献
11.
Biondini F Brunetti BG Candori P De Angelis F Falcinelli S Tarantelli F Moix Teixidor M Pirani F Vecchiocattivi F 《The Journal of chemical physics》2005,122(16):164307
The energetics of [Rg... N2O]* autoionizing collision complexes (where Rg=He or Ne) and their dynamical evolution have been studied in a crossed beam apparatus, respectively, by Penning ionization electron spectroscopy (PIES) and by mass spectrometry (MS) techniques in the thermal energy range. The PIES spectra, detected by an electron energy analyzer, were recorded for both complexes at four different collision energies. Such spectra allowed the determination of the energy shifts for Penning electron energy distributions, and the branching ratios for the population of different electronic states and for the vibrational population in the molecular nascent ions. For the [Ne...N2O]* collision complex it was found, by MS, that the autoionization leads to the formation of N2O+, NO+, O+, and NeN2O+ product ions whose total and partial cross sections were measured in the collision energy range between 0.03 and 0.2 eV. The results are analyzed exploiting current models for the Penning ionization process: the observed collision energy dependence in the PIES spectra as well as in the cross sections are correlated with the nature of the N2O molecule orbitals involved in the ionization and are discussed in term of the Rg-N2O interaction potentials, which are estimated by using a semiempirical method developed in our laboratory. 相似文献
12.
Yanyan Chen Ying Yu Haihong Wu Shurong Wang Baolin Zhu 《Journal of Dispersion Science and Technology》2013,34(2):245-249
N‐doped TiO2 nanotubes with high photocatalytic activity were prepared by the combination of sol‐gel process with hydrothermal treatment. The prepared materials are characterized with transmission electron microscopy (TEM), high‐resolution transmission electron microscopy (HRTEM), x‐ray diffraction (XRD), x‐ray photoelectron spectra (XPS), and UV‐vis spectra. Photocatalytic performance of the N‐doped TiO2 nanotubes is studied by testing the degradation rate of methyl orange under UV irradiation. Obtained results indicate that N‐doped TiO2 nanotubes have high catalytic activity for photocatalytic oxidation. 相似文献
13.
Kovac B Novak I 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2002,58(7):1483-1488
The electronic structure of coumarin derivatives has been investigated by a combination of UV photoelectron spectra (UPS), semi-empirical MO calculations and comparison with the spectra of related coumarins. The influence of substituents on the S0 and S1 electronic states energies is discussed. 相似文献
14.
Schultz T Clarke JS Gilbert T Deyerl HJ Fischer I 《Faraday discussions》2000,(115):17-31; discussion 79-102
We report picosecond time-resolved pump-probe photoelectron spectra of the allyl radical, C3H5, and the fully deuterated allyl, C3D5, carried out in order to elucidate the primary photophysical processes upon UV excitation. It is shown that the UV bands of allyl decay in a two-step process: the first step is an internal conversion to the lower-lying A-state within 20 ps or less, while the second step is a very fast decay from the A-state to the electronic ground state through a conical intersection. In addition we report the first zero kinetic energy (ZEKE) photoelectron spectrum of allyl, yielding an ionisation energy of 65762 cm-1. 相似文献
15.
UV photoelectron spectra of hypoxanthine, xanthine, and caffeine, up to 20 eV, were calculated and compared with the experimental spectra reported in literature. The calculations were performed using a novel version of the quantum mechanical symmetry-adapted cluster/configuration interaction (SAC-CI) method termed, direct SAC-CI. The Duning/Huzinaga valance double-zeta D95+(d,p) Gaussian basis set was also employed with this method. The ionization energies and intensities were calculated, and the corresponding spectral bands were assigned. Natural bonding orbital (NBO) calculations were employed for better spectral band assignment. The calculated ionization energies and intensities reasonably produced the experimental photoelectron spectra. 相似文献
16.
The electronic structures of the anti-HIV drug zidovudine (AZT) and antimalarial drug artemisinine have been investigated by UV photoelectron spectroscopy (UPS), MO calculations, and comparison with the spectra of related molecules. The analysis of their electronic structure is correlated with known biological activities. 相似文献
17.
It is demonstrated under which conditions the competition between autoionization and photoemission can give rise to extra peaks in UV photoelectron spectra. Experiments are performed with atomic oxygen and hitherto unobserved autoionization peaks are reported. 相似文献
18.
UV photoelectron spectra of matrix-isolated and condensed CO and N2 have been measured. The emission from the 4σ, 1π and 5σ orbitals show similar relaxation shifts of about 1 eV. This shift is 0.3 eV larger for the species isolated in xenon matrices. The width of the peaks is smaller by 0.3 eV in the Xe matrix in comparison with the pure solids but remains larger than those measured for the gas phase. 相似文献
19.
本文用半经验SCF-MO-HAM/3方法计算了胞嘧啶和它的某些甲基衍生物的电离能、激发能和振子强度.指认了这些分子的紫外光电子能谱和紫外电子光谱.讨论了在紫外光电子能谱指认上与CNDO/S的不同之处.分析了胞嘧啶在磷酸三甲酯中可能存在的主要异构体形式. 相似文献
20.
WANG Dan-dan YANG Jing-hai CAO Jian LANG Ji-hui GAO Ming LIU Xiao-yan . Key Laboratory of Excited State Processes Changchun Institute of Optics Fine Mechanics Physics Chinese Academy of Sciences Changchun P. R. China . Graduate School of Chinese Academy of Sciences Beijing 《高等学校化学研究》2011,(2):174-176
Eu-doped ZnO nanosheets were synthesized successfully by means of the hydrothermal method. The X-ray diffraction(XRD) pattern shows that the sample is a single phase with the ZnO-like wurtzite structure. And the X-ray photoelectron spectrum suggests that there are Eu3+ ions in the matrix of the sample. Eu3+-related red emissions resulted from energy transfer were observed for the nanosheets under UV laser excitation. The UV, green and yellow emissions were also seen in the photoluminescence spectra. 相似文献