Vibrational relaxation of excimers

Datsyuk, V. V.; Izmaǐlov, I. A.; Kochelap, V. A.

doi:10.1070/pu1998v041n04abeh000384

Cited by 16 publications

(6 citation statements)

References 84 publications

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“…The high excitation effi ciency of higher energy states (C 2 Π 1/2 and D 2 Π 3/2 ) of mercury monobromide molecules, as well as the dependence of the HgBr* exciplex radiation power on the sulfur hexafluoride partial pressure (the radiation power increases many times) [13], suggests that mole cules in these energy states occupy the state B 2 of The run of the dependence of the HgBr* exciplex radiation power on the nitrogen partial pressure (Fig. 3) depends on the (i) electron concentration, which increases with nitrogen partial pressure in the mixture; (ii) fraction of the discharge energy that is spent on heating the working mixture; (iii) electron mean energy; (iv) rate of dissociative excitation of the HgBr* exciplex by electrons and nitrogen molecules excited into the metastable states A 3 and B 3 Π g ; (v) popula tion of these states, which increases owing to the relax ation of the populations of higher vibrational levels in collisions with working mixture components, and (vi) quenching of the HgBr* exciplex by molecules of mer cury dibromide, sulfur hexafluoride, and nitrogen and also by atoms of helium [30][31][32][33][34][35]. A rise in the nitrogen partial pressure causes a decrease in parameter E/N and, accordingly, leads to an increase in the discharge power specific losses due to elastic scattering by atoms and molecules (heating of the mixture) [36].…”

Section: Discussion Of Resultsmentioning

confidence: 99%

Optical characteristics and plasma parameters of a blue-green exciplex lamp

Малинина

Shimon

2012

Tech. Phys.

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The optical characteristics and plasma parameters of an exciplex lamp radiating in the blue-green spectral range are studied. A plasma is generated by an atmospheric pressure barrier discharge initiated in a quaternary mixture including mercury dibromide, sulfur hexafluoride, nitrogen, and helium. It is shown that the exciplex lamp can radiate at an elevated repetition rate of pump pulses (1-12 kHz) under the conditions of mixture self heating. A tradeoff between the radiation power and nitrogen partial pressure is found. The mean specific radiation power in the blue-green range at a level of 480 mW/cm 3 is achieved at partial vapor pressures of mercury dibromide, sulfur hexafluoride, nitrogen, and helium of 0.70, 0.07, 4.00, and 117.20 kPa, respectively. The plasma parameters, namely, the electron energy distribution function; concentration, tem perature, and mean energy of electrons; transport properties; and rate constants of elastic and inelastic elec tron scattering by the working mixture components are determined as functions of ratio E/N (where E is the electric field strength and N is the total concentration of mercury dibromide, sulfur hexafluoride, and nitro gen molecules and helium atoms). It is found that mercury monobromide molecules and also excited and higher energy states take part in the population of exciplex molecules HgBr* (B 2 states) in the course of quenching these exciplexes by sulfur hexafluoride and nitrogen molecules.

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Section: Discussion Of Resultsmentioning

confidence: 99%

Optical characteristics and plasma parameters of a blue-green exciplex lamp

Малинина

Shimon

2012

Tech. Phys.

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“…In [15], interaction of excimers with plasma electrons was studied in the framework of the Bethe-Born approximation of the scattering theory. The following rate constant of an electron-induced molecular transition was obtained [15,16]:…”

Section: Molecular Transitions In Collisions Of Molecules With Plasma...mentioning

confidence: 99%

“…Earlier, this reaction was included in a kinetic model of the HgBr avalanche discharge laser [14]. A formula for the rate constant of a molecular transition induced by collisions of the molecule with plasma electrons was derived in our previous work [15,16]. This formula was used in a kinetic study of a HgBr lamp excited by single current pulses [17].…”

Section: Introductionmentioning

confidence: 99%

Direct electron-impact mechanism of excitation of mercury monobromide in a double-pulse dielectric-barrier-discharge HgBr lamp

Datsyuk

Izmaǐlov

Naumov

et al. 2016

Plasma Sources Sci. Technol.

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In a nonequlibrium plasma of a gas-discharge HgBr lamp, the terminal electronic state of the HgBr(B-X) radiative transition with a peak wavelength of 502 nm remains populated for a relatively long time and is repeatedly excited to the B state in collisions with plasma electrons. This transfer of the HgBr molecules from the ground state X to the excited state B is the main mechanism of formation of the light-emitting molecules especially when the lamp is excited by double current pulses. According to our simulations, due to the electron-induced transitions between HgBr(X) and HgBr(B), the output characteristics of the DBD lamp operating in a double-pulse regime are better than those of the lamp operating in a single-pulse regime. In the considered case, the peak power is calculated to increase by a factor of about 2 and the lamp efficiency increases by about 50%.

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“…In the literature there are almost no data which would allow to strictly determine a dependence of the relaxation process rates on vibrational structure. Especially, this concerns the rates of collision-induced deactivation of excimer molecules [45].…”

Section: Xe Concentration Effect On the Intensity Of Emission From Himentioning

confidence: 99%

“…The lower levels (V =0, 1 i 2) we will place in the second band. The first band width is largerthan a vibrational quantum, and the VT relaxation in it can be considered as diffusion in a quasicontinuous energy space [44,45]. The time of diffusion of molecules in the first band let us denote as t and a total time of thermalization of the vibrational subsystem in the second band as t2.…”

Section: Spectral Regimes Of the Xef Molecule Lasingmentioning

confidence: 99%

Excimer molecules. Halogenides of noble bases. Spectra of induced radiation.

Zubrilin¹

2002

Selected Papers From the International Conference on Spectroscopy of Molecules and Crystals

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Structure of stimulated emission spectra of noble gas monohalogenide molecular lasers is considered. Spectrum of KrF lasing on bound-to-free transitions is reported. Fine structure of stimulated emission spectra of molecules with shallow potential well in the ground state is considered by the example of XeCI and XeF molecules. The structure is due to rotations in XeCl and XeF. Influence of the active medium parameters (pressure, mixture composition) on the structure of XeF molecule stimulated emission spectrum structure as well as spectral performances of emission of XeF laser pumped by powerful electron beam and pulsed electric discharge are considered. The nature of the lasing spectrum in the region near 350 nm is discussed. The report is based mainly on the authors' studies.

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Vibrational relaxation of excimers

Cited by 16 publications

References 84 publications

Optical characteristics and plasma parameters of a blue-green exciplex lamp

Optical characteristics and plasma parameters of a blue-green exciplex lamp

Direct electron-impact mechanism of excitation of mercury monobromide in a double-pulse dielectric-barrier-discharge HgBr lamp

Excimer molecules. Halogenides of noble bases. Spectra of induced radiation.

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