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1.
L De Boni L T Fran?a H P Grieneisen M Janowicz T B Kist A R Consiglio J R Schoffen V Stefani C Termignoni 《Electrophoresis》1999,20(12):2493-2500
The phenomenon of electrophoresis in free solution has been studied theoretically down to the molecular level for decades. In addition, intermolecular photo-induced proton transfer reactions, which occur in a wide class of molecules (phenols and aminoarenes) as well as proteins (green fluorescent protein), were also studied extensively. However, the study of the effect of light-induced electrophoretic mobility changes of the analytes in electrophoresis was begun only recently. In the present work, capillary zone electrophoresis was chosen as the environment to measure the magnitude of these electrophoretic mobility shifts induced by light. Background electrolytes (running electrolytes) with high refractive indices were developed, allowing the capillary to work like an optical fiber. The experimental conditions for obtaining stable coupling and guided laser light along the liquid core are discussed. Experimental evidence of band compression is observed, leading to a solitary wave behavior of the analyte band (2-naphthol). These solitary waves result from competition between thermal diffusion (dispersion mechanism) and a nonlinear (band compression) effect due to the combined electrophoresis phenomenon and absorption of guided light by the molecules of the band (which are subjected to a "reversible intermolecular proton transfer reaction" as one of their decay routes). The possibilities of applying this effect to different methods and techniques are also discussed. 相似文献
2.
M. Diegelmann H. P. Grieneisen K. Hohla Xue-Jing Hu J. Krasinski K. L. Kompa 《Applied Physics A: Materials Science & Processing》1980,23(3):283-287
As an outcome of a systematic study of excitation kinetics and fluorescence spectra concerning theD′(3π2u
)→A′(3π2g
) transitions in homonuclear diatomic halogens and corresponding transitions in interhalogen molecules [1], this paper describes,
for the first time, TEA laser action in the three halogen monofluorides ClF, BrF, and IF. Output energies in the mJ range
were demonstrated in a fast TEA discharge arrangement at the wavelengths of 284.4, 354.5, and 490.8 nm for ClF, BrF, and IF,
respectively. The results suggest parameter scalability and wavelength tunability. 相似文献
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4.
H. P. Grieneisen R. E. Francke A. Lago 《Applied Physics A: Materials Science & Processing》1978,15(3):281-286
This paper reports the observation of a well defined radiation mode emitted from a superradiant dye laser pumped by a pulsed
nitrogen laser. Beam geometry and spatial coherence of the dye laser are studied in connection with the pumping geometry.
It is shown that under favorable pumping conditions most of the excited molecules radiate into the same spatial mode by stimulated
emission. The associated mode structure is also calculated based on a model of a properly phased dipole distribution. The
calculated emission pattern reproduces the observed far field pattern closely.
Work supported in part by CNPq and FINEP. 相似文献
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6.
S. Lederer H. Winter HP. Winter F. Aumayr 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,41(3):505-511
The energy loss of hydrogen atoms with energies of 400
eV and 1 keV is studied in coincidence with the number of emitted
electrons during grazing scattering from atomically clean and flat
KI(001) and LiF(001) surfaces. The energy loss spectra for
specific numbers of emitted electrons are analyzed in terms of a
binary interaction model based on the formation of transient
negative ions via local capture of valence band electrons from
anion sites. Based on computer simulations we derive for this
interaction scenario probabilities for the production of surface
excitons, for electron loss to the conduction band of KI, for
emission of electrons, and for formation of negative hydrogen
ions. The pronounced differences of data obtained for the two
surfaces are attributed to the different electronic structures of
KI and LiF. 相似文献
7.
A compact 14.5GHz electron cyclotron resonance (ECR) ion source for the production of slow, multiply charged ions has been constructed,with the plasma-confining magnetic field produced exclusively by permanent magnets.Microwave power of up to 175W in the frequency range from 12.75 to 14.SGHz is transmitted from ground potential via a PTFE window into the water-cooled plasma chamber which can be equipped with an aluminum liner.The waveguide coupling system serves also as biased electrode,and two remotely-controlled gas inlet valves connected via an insulating break permit plasma operation in the gas- mixing mode.A triode extraction system sustains ion acceleration voltages between 1kV and 10kV.The ECR ion source is fully computer-controlled and can be remotely operated from any desired location via Ethernet. 相似文献
8.
Iodine vapour is optically excited in a two-step process populating selectively the first four vibrational levels of an ion-pair state having Te = 47032 ± 6 cm?1 and ωe = 98 ± 2 cm?1. Fluorescence from this state is observed at 340 nm with vibrational resolution and is found to terminate on levels of the intermediate B state. 相似文献
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10.
Pair absorption from colliding Xe atoms of the molecular fluorine laser radiation is reported. The absorption coefficient for this process at 300 K was found to be α = (4.32 ± 0.1) × 10-9Torr-2cm-1. Fluorescence at 172 nm originating predominantly from the state of Xe12 indicates that by this mechanism the Xe dimer laser can be pumped optically. 相似文献