Xenon Resonance Line Research Articles

Simulation of emission spectra of the gas-discharge plasma of a krypton-xenon mixture

The narrow-band radiation observed in the range of the resonance line of xenon at 147 nm in the VUV emission spectra of the gas-discharge plasma of a krypton-xenon mixture is proposed to interpret as a manifestation of bound-bound transitions between the vibrational levels of the excited electronic states 0+(3P1) and 1(3P1) and the ground electronic state 0+(1S0) in the KrXe* molecule. A correction of the potential curves of the electronic states under consideration is proposed from a comparison of the calculated and experimental spectra.

Mechanism for generating stimulated VUV emission of the Xe*Kr dimer in a dc capillary discharge

The emission spectrum of a dc capillary discharge in krypton with a small (≤0.1%) xenon impurity has been experimentally studied in the 115-850-nm range. It is shown that most of the radiation energy is concentrated in a narrow VUV spectral band adjacent to the 146.96-nm resonance line of xenon and belonging to the heteronuclear Xe*Kr molecule. The power of the narrow-band VUV radiation and its angular dependence have been measured. A conclusion is drawn that the appearance of the narrow-band VUV radiation represents amplified spontaneous emission caused by transillumination of the broad-band amplifying medium by a narrow-band "seed."

Stimulated emission of inert gas mixtures in the VUV range

Amplification properties of continuous VUV emission of cooled discharge in mixtures of heavy inert gases are studied experimentally. The discharge current is 10–50 mA, the pressure is 100 GPa. Results pointing to amplification near the resonance line of xenon λ=146.96 nm are obtained. The amplification coefficient is measured to be κ=0.1 cm−1. The problem of radiation outcoupling from the active medium remains to be solved for practical implementation of a VUV laser.

Application of dichroic mirror for improvement of luminance and luminous efficacy in an alternating current plasma display cell

An alternate application of dichroic mirror for the improvement of luminance and luminous efficacy in an ac plasma display panel (PDP) is suggested. Since only part of the vacuum ultraviolet (VUV) generated in the PDP cell is used to excite the phosphor, we propose deploying a dichroic mirror that increases luminance and efficiency by reflecting part of the VUV toward the phosphor. The optical constants of the dielectric layers of the dichroic mirror and a protecting layer of a PDP were determined from the measurements of reflectance and transmittance of the corresponding films and they were used to design the dichroic mirror including the protecting layer. The 147 nm xenon resonance line is usually used to activate the phosphor in the PDP cell. Thus, we designed the dichroic mirror to have a high reflectance for the VUV centered around 147 nm and a high transmittance for the visible light. We investigated the usefulness of the dichroic mirror by comparing the luminance and luminous efficacy of test panels with and without the dichroic mirror and found it could increase the luminance by 20%–31% and the luminous efficacy by 25%–34%.

Absorption measurements of krypton and xenon resonance lines

In this study the absorption of KrI and XeI resonance lines has been measured as a function of pressure ( P ⩽ 100 mbar) at room temperature ( T = 292 K). Already at low particle densities these lines show a deviation from a symmetrical profile. In addition structures arise which can be partly ascribed to molecular absorption of the Xe 2 and Kr 2 dimer. The red wing of the first xenon resonance line (1469.61 Å) has been studied showing the validity of the quasistatic theory in the nearest neighbour approximation for the interpretation of line wings. For this purpose the dependence of the absorption coefficient on particle density and frequency difference from the line center ( Δv) has been investigated. Difference potentials of the kind ΔV(r) = h( γ M C 3 r 3 − ΔC 6 r 6 ) were used to fit the line wing, deducing the value for ΔC 6.

Vacuum ultraviolet afterglow emission of rare gases and their mixtures

The results of a study of afterglow in the VUV spectral region of discharges in xenon, krypton and argon (at pressures of 0.2 to 6 Torr) are reported. Values have been obtained for recombination coefficients and formation rates of molecular ions from atomic ions, as well as for certain collisional excitation transfer constants for the 3p54s1P1 level of argon by comparing the experimental pressure dependence of resonance-line afterglow intensities with approximate analytical solutions of balance equations. The time dependence of xenon resonance lines in mixtures of helium, neon, argon and krypton were also compared with approximate solutions of the balance equations. The rate constant for the formation of xenon molecular ions in three-body collisions of Xe+ with two Xe atoms was measured to be k+(Xe)=0.8(+or-10.2)*10-31 cm6 s-1 with Ne as the third atom the same reaction had a constant of k+(Ne)=3.0(+or-0.8)*10-31 cm6 s-1 and with Ar as the third atom k+(Ar)=0.8(+or-10.2)*10-32 cm6 s-1. The Kr2+ formation constant in three-body collisions of Kr+ with two Kr atoms was measured to be 0.53(+or-0.15)*10-31 cm6 s-1 and, for Ar2+ formation in a similar reaction with two argon atoms, it is 1.9(+or-0.5)*10-31 cm6 s-1. The recombination constants alpha for the atomic ions were obtained: alpha 1(Xe)=1.5(+or-0.5)*10-9, alpha 1(Kr)=0.8(+or-0.2)*10-9, and alpha 1(Ar)=1.0(+or-10.2)*10-10 cm3 s-1.

Gas phase photolysis of 1-pentene at 147 nm (8.4 eV)

The photolysis of gaseous 1-pentene was carried out in a static system using the xenon resonance line at 147 nm (8.4 eV) at pressures in the range 0.5 – 400 Torr (0.7 – 533 hPa). Only decomposition processes were studied and no attempt was made to establish the pattern of free radical reactions. The major dissociation products observed were ethylene, allene, propylene, 1,3-butadiene, acetylene and propyne. The minor products included methane, ethane, propane, some C 5H 8 and C 4H 6 hydrocarbons, and 1-butene. The radical species were identified using scavengers such as oxygen, H 2S and HI. The pressure dependence of the yields of the major radicals (C 3H 5, CH 3, C 2H 5, C 2H 3 and C 3H 7) was established. The C 2H, C 4H 5, C 4H 7, CH 2 and C 3H 3 radicals were found to be unimportant. The primary decomposition channels are established. The main processes are the cleavage of a CH bond with a yield φ of 0.45 – 0.48 and the cleavage of a CC bond with a yield φ of 0.47. The allylic CC bond appears to be the only CC bond which undergoes primary rupture. All four primary intermediates, i.e. C 5H 9, C 3H 5, C 2H 5 and H, are energized. The radicals either decompose (isomerization prior to decomposition is possible in some cases) or undergo collisional stabilization; some hydrogen atoms add to the double bond prior to thermalization. Some details of the secondary processes are established but the overall mechanism is too complex to be fully interpreted.

Gas phase photolysis of 1-butene at 147 nm (8.4 eV)

The photolysis of 1-butene was carried out in a static system using the xenon resonance line at 147 nm (8.4 eV) at pressures in the range 15 – 500 Torr (2 – 66.5 kPa). The major products observed were acetylene, ethane, ethylene, allene, propyne, 1,3-butadiene and isopentane. The radical species were identified by using scavengers such as oxygen and H 2S. Evidence is presented for the occurrence of ten primary processes to which quantum yields have been ascribed. The main process is a β cleavage of the CC bond which occurs with a yield of φ = 0.51. A hydrogen atom mechanism involving the occurrence of hot hydrogen atoms (about 30% of them have an excess energy of about 0.26 eV) was proposed to account for the pressure dependence of propylene. Dissociation of excited radicals contributes to the formation of allene and propyne.

Gas phase photolysis of 1-pentene and 1-pentene-d10 at 7.1 and 7.6 eV. Kinetic considerations

The gas phase photolysis of n-pentene was carried out in a static system using nitrogen resonance lines at [Formula: see text] and the bromine line at [Formula: see text] The mechanism for the photolysis was proposed and compared to what was concluded at 8.4 eV (147 nm, the xenon resonance line). The kinetics of the decomposition of the excited C3H5* radicals formed in the primary photochemical process and the C5H11* radicals formed by the addition of hydrogen atoms to the parent molecules were discussed. The investigations were extended to the n-C5D10 photolytic System. The observed decomposition rate constants of the excited pentyl radicals as well as the secondary non-equilibrium isotope effects agree with the data published earlier. It is concluded from these experiments that, at least at 7.6 eV, hot hydrogen atoms are produced.Only a small fraction of the C3H5* radicals décompose and yield aliène. At the same time the combined primary–secondary non-equilibrium isotope effects are much less than those calculated for the 'pure' primary isotope effects. To account for these observations, it is assumed that the C3H5* radicals are formed with a wide spread in the internal energies. Since the threshold of the decomposition of the excited C3H5* radical lies above its mean excess energy (calculated on the statistical basis), an analogy in the energy-distribution functions on the radicals activated photochemically and thermally may be suggested. If so, an inverse secondary isotope effect may contribute to the gross effect involved in the C3H5* radical decomposition.

Photolysis of Spiropentane with Xenon Resonance Line

AbstractSpiropentane was photolyzed using xenon 1470Å resonance light source at room temperature. The photolysis products were analyzed by means of FID‐gas‐chromatographic technique. Through the information about the yields of products, the major primary process of this light‐molecule interaction was assigned as C‐C bond breakage. Methylenecyclobutane, which has been an identified isomerization product of excited spiropentane molecule, was not able to be produced at present high excitation energy.

Gas phase photolysis of 1-butene at 147 nm (8.4 eV)

The photolysis of 1-butene was carried out in a static system using the xenon resonance line at 147 nm (8.4 eV) at pressures in the range 15 – 500 Torr (2 – 66.5 kPa). The major products observed were acetylene, ethane, ethylene, allene, propyne, 1,3-butadiene and isopentane. The radical species were identified by using scavengers such as oxygen and H 2S. Evidence is presented for the occurrence of ten primary processes to which quantum yields have been ascribed. The main process is a β cleavage of the C-C bond which occurs with a yield of φ = 0.51. A hydrogen atom mechanism involving the occurrence of hot hydrogen atoms (about 30% of them have an excess energy of about 0.26 eV) was proposed to account for the pressure dependence of propylene. Dissociation of excited radicals contributes to the formation of allene and propyne.

The Wavelength Stability of the Resonance Line of Xenon (XeI, λ147 nm)

The variation of wavelength of the natural xenon line λ147 nm has been measured as a function of xenon pressure (10-10 to 10-4 torr) and discharge current (10 to 50 mA DC) in a lamp which has a limited discharge depth of 8 mm behind the window. Any variations with source conditions that are present are less than ±4 fm (0.04 mÅ) or 2.7 parts in 108. At higher pressures the line becomes asymmetrical.

ESR study of the xenon-photosensitized decomposition of gaseous hydrogen

The gas-phase ESR technique has been used to study the xenon-photosensitization of hydrogen. The ESR spectrum of atomic hydrogen was observed when the mixtures of xenon and hydrogen were irradiated by the xenon resonance line (147 nm). The results show that photosensitized decomposition of hydrogen takes place due to the chemical quenching of the excited xenon by hydrogen molecules.

Solid state polymerization of several monomers by vacuum ultraviolet rays

AbstractSolid state polymerization of acrylonitrile and acetylene initiated by a vacuum ultraviolet radiation (Xenon resonance line, 8.44 e. v.) has been studied at low temperatures in a range of −100 to −196°C. The color of polymers obtained ranged from nearly white to brownish yellow. It was found from infrared spectra of the polymers that the structure of the polyacrylonitriles obtained by vacuum ultraviolet irradiation is quite different from that of the polyacrylonitriles obtained by γ‐rays or accelerated electrons irradiation. In the polymers obtained by γ‐rays, the nitrile groups remain unreacted but in the case of vacuum ultraviolet the number of unreacted nitrile groups decreases with decreasing polymerization temperature. It may be concluded that in the case of vacuum ultraviolet irradiation the polymerization reaction takes place both in nitrile and vinyl groups, and thus the ring is formed by an intramolecular linkage. The apparent activation energy was obtained from the initial rate as 3.1 kcal./mole (−100 to −130°C.) and 0.06 kcal./mole (−130 to −196°C.). The quantum yield in the polymerization at −196°C. was estimated to be about 0.2 and the G value was about 2. G value in γ‐ray‐initiated polymerization at −196°C. was 102 ∼ 103. The extreme differences between the G values may be attributed to the energy differences of radiations for the initiation reaction.

Ultraviolet Photochemistry of Some Frozen Gases

Here Seems to be Agreement that laboratory studies are necessary in the pursuit of a better understanding of the interstellar medium. Herein is described some experiments performed on the effects of far ultraviolet radiation on molecules containing the astronomically abundant atoms H, O, C, and N. In particular, the attempts that have been made to prepare, isolate, and identify various free radicals and other reactive species, some of which may play a role in the processes occurring in the interstellar medium, are discussed.In one of the studies, a frozen film of pure carbon dioxide at 77° K was irradiated with the light from a low pressure xenon discharge lamp equipped with a LiF window. This lamp is activated by radio-frequency radiation, and the emitted light is rich in the 1470-Å resonance line of xenon.