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1.
Treatment of the predissociation of the A1Σu+ state of As2 by the interaction with a repulsive state
The rotational analysis of the electronic spectrum of the As2 molecule has shown a strong predissociation in the A1Σu+ state above the v = 7 level. The resultant widths of the rotational absorption lines have been measured for the vibrational levels v = 9 to 15. The numerous experimental data allowed us to consider the predissociation state as a repulsive one according to the C+ predissociation case described by Mulliken. A numerical treatment based on a semiclassical method has been performed in order to obtain a good representation of the potential curve of the repulsive state near the crossing point. 相似文献
2.
B. Zhang I. Dugandžić J. Bauer M. Baier F. E. Wagner V. E. Antonov T. E. Antonova S. M. Filipek 《Hyperfine Interactions》1992,69(1-4):471-474
Hydrides of Ni0.70Cu0.30 prepared both electrolytically and under high pressures of hydrogen gas were studied by Mössbauer spectroscopy on dilute57Fe probes and by magnetization measurements. At hydrogen-to-metal ratios abovex≈0.3 no ferromagnetism is observed down to 4.2 K. The dependence of the mean change of the isomer shift on the hydrogen content of the samples reveals a repulsive interaction between the hydrogen interstitials and the iron probes. The effect of this interaction is, however, less pronounced than for57Fe in the hydrides of pure nickel. This difference can be attributed to a competition of the repulsive Fe?H and Cu?H interactions. 相似文献
3.
Enhancement of Europium Luminescence in Tetracycline–Europium Complexes in the Presence of Urea Hydrogen Peroxide 总被引:2,自引:2,他引:0
An increase in the europium emission band was observed, for the first time, with addition of urea hydrogen peroxide to the
tetracycline–europium (Tc–Eu)solution. We have observed that the wavelength, the band width and the area of 5D0→7F2 europium transition change with the urea hydrogen peroxide concentration. We claim that the tetracycline–europium complexes
can be used as probes of urea hydrogen peroxide concentration. 相似文献
4.
S.N. Nakamura K. Bartlett G.A. Beer G.R. Gill R.S. Hayano T.M. Ito M. Iwasaki L. Lee G. Mason A. Olin H. Outa M. Salomon R. Seki T. Taniguchi T.P. Terada G. Trayling Y. Yamashita S. Yen 《Hyperfine Interactions》1999,118(1-4):45-51
We successfully observed clear K-series kaonic hydrogen X-rays for the first time taking advantage of two charged pions tagging technique and a gaseous hydrogen
target. The strong-interaction energy shift and width of 1s state of K
−p atom were determined to be ΔE
1s
= -323 ± 63 (statistical) ± 11 (systematic) eV and Г1s = 407 ± 208 ± 100 eV. Our result means that the K
−p strong interaction near threshold is repulsive and the long-standing kaonic hydrogen puzzle is solved.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
5.
Dmytro V. Piatnytskyi Oleksiy O. Zdorevskyi Sergiy M. Perepelytsya Sergey N. Volkov 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2015,69(11):255
Changes in the medium of biological cells under ion beam irradiation has been considered as a possible cause of cell function disruption in the living body. The interaction of hydrogen peroxide, a long-lived molecular product of water radiolysis, with active sites of DNA macromolecule was studied, and the formation of stable DNA-peroxide complexes was considered. The phosphate groups of the macromolecule backbone were picked out among the atomic groups of DNA double helix as a probable target for interaction with hydrogen peroxide molecules. Complexes consisting of combinations including: the DNA phosphate group, H2O2 and H2O molecules, and Na+ counterion, were considered. The counterions have been taken into consideration insofar as under the natural conditions they neutralise DNA sugar-phosphate backbone. The energy of the complexes have been determined by considering the electrostatic and the Van der Waals interactions within the framework of atom-atom potential functions. As a result, the stability of various configurations of molecular complexes was estimated. It was shown that DNA phosphate groups and counterions can form stable complexes with hydrogen peroxide molecules, which are as stable as the complexes with water molecules. It has been demonstrated that the formation of stable complexes of H2O2-Na+-PO4 - may be detected experimentally by observing specific vibrations in the low-frequency Raman spectra. The interaction of H2O2 molecule with phosphate group of the double helix backbone can disrupt DNA biological function and induce the deactivation of the cell genetic apparatus. Thus, the production of hydrogen peroxide molecules in the nucleus of living cells can be considered as an additional mechanism by which high-energy ion beams destroy tumour cells during ion beam therapy. 相似文献
6.
It is shown that the lack of information on the rotational structure of the vibrational terms of a diatomic molecule in the problem of determination of the potential well of the molecule can be compensated by information on the intensity distribution in the spectrum of a bound-free transition to a repulsive branch of the state under study. The accuracy characteristics of the method proposed are studied on the example of a potential whose parameters are close to those of the state a 3Σ u + of the Na2 molecule. 相似文献
7.
JOSEPH A. KUNC 《Molecular physics》2013,111(3):413-420
Partition functions for both the rotational modes (hindered internal rotation and overall rotation) of the hydrogen peroxide (H2O2) molecule in the ground electronic state are studied using quantum and classical Gibbsian statistical mechanics. The partition functions are used to calculate rotational thermodynamic functions (internal energy, enthalpy, Helmholtz free energy, Gibbs free energy and entropy) of a hydrogen peroxide gas of weakly interacting molecules at temperatures above 300 K. 相似文献
8.
Juan Poyato José Luis Pérez-Rodríguez Verónica Ramírez-Valle Anton Lerf Friedrich E. Wagner 《Ultrasonics sonochemistry》2009,16(4):570-576
Sonication in a 1:1 mixture (volume ratio) of water and concentrated H2O2 (30%) is a soft method for particle size reduction of phyllosilicate minerals like vermiculites. Repeated sonication causes a particle size reduction to about 70 nm for the Santa Olalla and to 45 nm for the Ojén-vermiculite. In this context the question arises whether the strong oxidising effect of the hydrogen peroxide affects the oxidation state of the iron in the vermiculites. Therefore, the Fe3+/Fetotal ratio before and after sonication was determined by means of Mössbauer spectroscopy. Whereas this ratio was found to remain almost constant in the Santa Olalla vermiculite, it increased from 0.79 to 0.85 in case of the Ojén sample. In the latter case, the oxidation is accompanied by a decrease of the layer charge.Surprisingly, sonication in pure water leads to a decrease of the Fe3+/Fetotal ratio in the case of the Ojén-vermiculite, i.e., to an increase of the Fe2+ fraction to roughly twice the value before sonication. Again the Fe3+/Fetotal ratio of the Santa Olalla vermiculite remains unchanged. The surface area SBET of the reduced Ojén-vermiculite amounts to 50 m2/g, which is close to the value obtained in the presence of hydrogen peroxide. The results presented should be taken as a warning that particle size reduction by sonication may be accompanied by a change of the redox state and the layer charge of the material. 相似文献
9.
The reactive oxygen species hydrogen peroxide (H2O2) was detected cytochemically in Solanum tuberosum cv. Rywal tissues as a hypersensitive response (HR) 24 and 48 h after a Potato virus Y (PVY) infection.Hydrogen peroxide was detected in vivo by its reaction with 3.3-diaminobenzidine, producing a reddish-brown staining in contact with H2O2. Hydrogen peroxide was detected in the necrotic area of the epidermal and mesophyll cells 24 and 48 h after the PVY infection. Highly localised accumulations of H2O2 were found within xylem tracheary elements, and this was much more intensive than in non-infected leaves. Hydrogen peroxide was detected cytochemically in HR also by its reaction with cerium chloride, producing electron-dense deposits of cerium perhydroxides.Inoculation with PVYNTN and also PVYN Wi induced a rapid hypersensitive response during which highly localised accumulations of H2O2 was detected in plant cell walls. The most intensive accumulation was present in the bordering cell walls of necrotic mesophyll cells and the adjacent non-necrotic mesophyll cells. Intensive electron-dense deposits of cerium perhydroxide were found along ER cistrenae and chloroplast envelopes connected with PVY particles. The precipitates of hydrogen peroxide were detected in the nuclear envelope and along tracheary elements, especially when virus particles were present inside. The intensive accumulation of H2O2 at the early stages of potato–PVY interaction is consistent with its role as an antimicrobial agent and for this reason it has been regarded as a signalling molecule. 相似文献
10.
I. S. Baikova E. V. Shtamm E. V. Vichutinskaya Yu. I. Skurlatov 《Russian Journal of Physical Chemistry B, Focus on Physics》2009,3(2):251-256
The kinetic characteristics of the oxidation of iron monosulfide with molecular oxygen and hydrogen peroxide in a neutral aqueous medium were studied. The rate of oxidation of FeS with oxygen was proportional to the concentration of O2 and quadratically depended on the initial concentration of FeS, W 0 = k ef [FeS]2[O2], where k ef = (2.5 ± 0.5) × 105 M?2 s?1 (pH 8, 22°C). During the oxidation of FeS, the iron ion retained the valence state +2. Oxidation products contained about 50% elemental sulfur. The interaction of FeS with H2O2 was characterized by the half-time of reaction less than 15 s. The products of oxidation of initially nontoxic FeS contained toxic compounds, supposedly the sulfoxylate ion HS 2 ? . 相似文献
11.
Alex Zunger 《Journal of Physics and Chemistry of Solids》1975,36(4):229-238
The truncated crystal method is used to describe the band gap, work function, repulsive ground state crystal potential, Davydov excitons and defect states due to H and N2 impurities, in molecular Pa3 hydrogen crystal, utilizing a simplified minimal basis set and semiempirical quantum chemical methods. Favorable results are achieved regarding experimental optical data. 相似文献
12.
M. Vogler 《Zeitschrift für Physik A Hadrons and Nuclei》1978,288(1):7-10
The velocity distributions of H-H fragment pairs arising from dissociative collisions of 10keV H 2 + ions incident on H2, He, and Ar were measured using a flight-time-difference method. The H 2 + ions were produced in an electron impact ion source at two different electron energies, at 100eV and 18eV. The influence of the electron energy on the fragment velocity distributions is studied. Conclusions are drawn on the processes which lead to the formation of neutral fragment pairs. Electron capture into the repulsive b3 Σ u + state of H2 plays a dominant role. 相似文献
13.
E. Giamello P. Rumori F. Geobaldo B. Fubini M. C. Paganini 《Applied magnetic resonance》1996,10(1-3):173-192
The interaction of hydrogen peroxide with various metal oxides has been followed by EPR in the aim of investigating the paramagnetic species formed along the complex processes of H2O2 decomposition and interaction with the oxide. Data are reported about three systems (MgO, ZrO2 and Me2+/Y zeolite) which are representative of three classes of oxides (insulators, semiconductors and aluminosilicate molecular sieves). Several radical species have been put into evidence in the various cases. The superoxide O 2 ? ion has been observed in all cases while in the case of MgO also the OH radical and the O? radical ion have been identified. In the case of Zn2+/Y zeolite, beside the superoxide radical anion, a new signal is observed which shows up upon treating the sample at 640 K and which is preliminarily assigned to a species in the triplet state in the zeolitic cavity. 相似文献
14.
BORIS MINAEV OLEKSANDR LOBODA ZILVINAS RINKEVICIUS OLAV VAHTRAS HANS ÅGREN 《Molecular physics》2013,111(15):2335-2346
The fine structure constant (electron spin-spin coupling) and the hyperfine structure parameters (electron-nuclear spin coupling, including spin-rotation and electron-nuclear quadrupole coupling) in the low-lying triplet states b3Σ+ u, a3Σ+ g and e3Σ+ u of molecular hydrogen and deuterium are calculated using a recently developed technique with full configuration interaction and multiconfiguration self-consistent field wave functions. The second-order spin-orbit coupling contribution to the 3Σ+ states splitting is negligible, and the calculations therefore provide a good estimate of the zero-field splitting based only on the electron spin-spin coupling values. For the bound a3Σ+ g state a negligible zero-field splitting is found, in qualitative agreement with the e-a spectrum. The zero-field splitting parameter is considerable for the repulsive b3Σ+ u state (?1 cm?1) and of intermediate size for the bound e3Σ+ u state. The isotropic hyperfine coupling constant is very large not only for the valence b3Σ+ u state (1580 MHz) but also for the Rydberg a and e triplet states (?1400 MHz). The quadrupole coupling constants for the deuterium isotopes are negligible (0.04–0.07 MHz) for all studied triplet states. The electric dipole activity of the spin sublevels in the triplet-singlet transitions to the ground state is estimated by means of the quadratic response technique. 相似文献
15.
G. Guillon T. Stoecklin 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2006,39(3):359-371
A comparative study of the inelastic
scattering
of 14N2
+ and
14N2 in collision with 3He atoms is presented. The
unrestricted nearside-farside (NF) method proposed by
Connor [J. Chem. Phys. 104, 2297 (1995)] is applied to analyse the Close
Coupling rotationally state selected angular distributions for four kinetic
energies. These four energies illustrate different regimes of the dynamics.
The relationships between the structures of the calculated differential
cross-sections (DCS) and the different regions of the potential energy
surfaces involved which can be extracted from semi classical models are here
easily obtained from a simple reading of the (NF) figures. At the
higher energy far-off the wells (1000 cm-1) the shape of the DCS are
quite similar for the two systems and their nearside-farside components
also, showing that the inelastic process is controlled by the short range
repulsive part of the potential which is essentially the same for these two
collisions. When the energy is decreased the differences between the two
wells associated with the He–N2
+ and He–N2 complexes are
responsible for the differences between the DCS for the two systems. The
farside component associated with the well become more and more prominent
for the elastic scattering while inelastic scattering remains controlled by
the repulsive core in a large angular interval. The nearside farside
analysis gives also a new picture of a resonance which is regarded as an
equilibrium between the repulsive and the attractive parts of the potential. 相似文献
16.
In this review, we have focused on the oxidation reactions of single dye molecules by reactive oxygen species (ROS). The methodologies
for the single-molecule detection of ROS, such as hydroxyl radical (HO•), singlet oxygen (O2(a1Δg)), and hydrogen peroxide (H2O2), have been introduced together with examples. In particular, a successful application using the single-molecule fluorescence
technique for the investigation of the TiO2 photocatalytic oxidation reactions is demonstrated in detail. 相似文献
17.
在低温条件下采用定向刻蚀技术, 对金属Ti片表面用H2O2溶液进行刻蚀氧化, 制备了垂直生长的纳米TiO2叶片状阵列薄膜电极. 通过X射线衍射分析表明, 纳米TiO2叶片状阵列薄膜经500 ℃下烧结1 h后, 从无定型转变为锐钛矿相. 场发射扫描电子显微镜观察表明: 在80 ℃下的H2O2溶液刻蚀氧化, 经1 d制备得到的是Ti片表面垂直生长的叶片状阵列, 其形貌均匀且完整地
关键词:
2')" href="#">纳米TiO2
叶片状阵列电极
染料敏化太阳电池
电子传输 相似文献
18.
We have computed the emission spectra of relaxing excitated-state systems in solids as a function of the rates of radiative decay (γ) from excited to ground state and non-radiative decay (γ) within the excited state. When these are comparable a pronounced dip is obtained in the central region of the spectrum, which then may have the appearance of two distinct, unrelated emission bands. The computations well reproduce the observed W and M2 bands in Ar crystals. Accordingly, these arise from the initially excited and near repulsive regions of the A1Σ+ emitting state, respectively. 相似文献
19.
Wolfgang Goy Volkmar Kohls Harald Morgner 《Journal of Electron Spectroscopy and Related Phenomena》1981,22(3):383-386
We have investigated the Penning ionization of NO2(2A1) by He(23S) by means of electron—ion coincidence measurements. It is possible to identify two entrance channels. The quartet state is essentially repulsive and gives rise to an electron energy spectrum similar to that found in photoionization. The doublet entrance channel is strongly attractive with a well depth De of 4.8 {?0.3+0.1 eV. Ionization out of this channel leads to very broad features in the electron energy spectrum. 相似文献
20.
Tatsuya Hashimoto 《Journal of Molecular Spectroscopy》2006,235(1):104-110
A new 3Π-3Σ band was observed in a discharge plasma of the nitrogen molecule and helium using near-infrared diode laser kinetic spectroscopy. All the lines in this band exhibited line broadening of more than 0.1 cm−1. Rotational analysis revealed that the lower state of the transition was the state of N2, which had already been studied in the D3Σ-E3Σ band. The term value and rotational constant suggested that the upper state is the G3Πu Rydberg state with an electron configuration of (N2+:X2Σ core)(3pπu). The line broadening is attributed to predissociation through a homogeneous interaction with a repulsive Πu state. 相似文献