Photolyse des Äthylens im Bereich 147 — 193 nm / Ethylene Photolysis At 147 — 193

1972 ◽  
Vol 27 (4) ◽  
pp. 628-638 ◽  
Author(s):  
P. Potzinger ◽  
L. Glasgow ◽  
G. Bünau
Keyword(s):  
Light Intensity ◽  
Kinetic Analysis ◽  
Photon Energy ◽  
Pressure Dependence ◽  
Experimental Parameters ◽  
193 Nm ◽  
Tentative Correlation

Abstract Ethylene photolysis was investigated at 147, 163, 185 and 193 nm. The following three primary processes were observed at all wavelengths C2H4 + hν → C2H2 + H2, (1) C2H4 + hν → C2H2 + 2H, (2) C2H4 + hν → C2H3 + H. (3) (1) was independent of all experimental parameters tested: temperature, pressure, wavelength, scavenger, and light intensity. (2) decreases with increasing pressure and increases with increasing photon energy. (3) shows almost no pressure dependence at 185 nm and decreases in importance with increasing photon energy. A kinetic analysis shows that participation of at least three different states of ethylene must be invoked to explain the results. A tentative correlation of these states with the spectroscopic states of ethylene is given.

Vibrational Energy Distributions of NH2(X̃2B1) Fragments Generated in the Photolysis of NH3at 193 nm:  Application of Kinetic Analysis on Vibrational Cascade

2002 ◽  
Vol 106 (34) ◽  
pp. 7728-7735 ◽  
Author(s):  
Katsuyoshi Yamasaki ◽  
Akihiro Watanabe ◽  
Teruaki Kakuda ◽  
Akira Itakura ◽  
Hirofumi Fukushima ◽  
...  
Keyword(s):  
Kinetic Analysis ◽  
Vibrational Energy ◽  
Energy Distributions ◽  
193 Nm

PHOTOINDUCED PHASE TRANSITION IN SINGLE CRYSTALS ON URETHANE-SUSTITUTED POLYDIACETYLENES

2001 ◽  
Vol 15 (28n30) ◽  
pp. 3969-3972 ◽  
Author(s):  
Hiroaki Tachibana ◽  
Noriko Hosaka ◽  
Masayuki Osaki ◽  
Yoshinori Tokura
Keyword(s):  
Phase Transition ◽  
Absorption Band ◽  
Light Intensity ◽  
Single Crystals ◽  
Photon Energy ◽  
Room Temperature ◽  
Photogenerated Electron ◽  
Reflectance Spectra ◽  
Electron Hole

Thermochromic behaviors were investigated by measurements of reflectance spectra for urethane-substituted polydiacetylene crystal having side groups of R=(CH)2)6OCONHC2H5 (PDA-6UEt). The PDA-6UEt crystal shows an irreversible thermochromic A-to-B (blue-to-red) phase transition: the absorption band at 1.88 eV due to the lowest exciton shifts to higher energy (2.15 eV) in the heating run, but the reflectance spectra remain in the B phase even when cooled down to room temperature. We have demonstrated that photoinduced phase transition (PIPT) is observed by utilizing the irreversible A-to-B phase transition. The conversion shows the presence of a threshold of the light intensity and depends on photon energy, suggesting that the PIPT is mediated by the photogenerated electron-hole pairs.

scholarly journals MISKONSEPSI MAHASISWA TENTANG EFEK FOTO LISTRIK

2020 ◽  
Vol 12 (2) ◽  
pp. 113
Author(s):  
Hamdani Hamdani
Keyword(s):  
Light Intensity ◽  
Diagnostic Test ◽  
Photon Energy ◽  
Electron Emission ◽  
Cutoff Frequency ◽  
Multiple Choice ◽  
Photoelectric Effect ◽  
Female Students ◽  
Male And Female

AbstractThis research was conducted to reveal students' misconceptions about the photoelectric effect. There were 58 students (13 male and 45 female) who answered 12 diagnostic test questions in the form of multiple-choice with open reasons. Misconceptions revealed include the order in which the colors of the rainbow disrupt photon energy; light intensity is affected by frequency; electron emission will occur when the light intensity and frequency of light are changed even though the frequency of the light used is smaller than the cutoff frequency. Male and female students have the same opportunity to misconceptions.Keywords: Misconception, Photoelectric Effect, Gender  

Charge Carrier Generation by Exciton-Exciton Annihilation in Poly(Di-N-Hexylsilane)

1992 ◽  
Vol 247 ◽  
Author(s):  
R. G. Kepler ◽  
Z. G. Soos
Keyword(s):  
Thin Films ◽  
Light Intensity ◽  
Charge Carrier ◽  
Energy Range ◽  
Photon Energy ◽  
Generation Mechanism ◽  
Photon Energy Range ◽  
Carrier Generation ◽  
Exciton Annihilation

ABSTRACTWe have studied charge carrier generation by photons in thin films of poly(di-n-hexylsilane) over the photon energy range 3.15 to 6 eV and find that it is nonlinear in light intensity to above 4.5 eV. We show that the generation mechanism is exciton-exciton annihilation.

Electronic Stimulation of Acceptor Reactivation IN p - Type Hydrogenated GaAs

1990 ◽  
Vol 184 ◽  
Author(s):  
I. Szafranek ◽  
G. E. Stillman
Keyword(s):  
Light Intensity ◽  
Photon Energy ◽  
Vibrational Excitation ◽  
Strong Dependence ◽  
Saturation Level ◽  
Sample Temperature ◽  
Bandgap Energy ◽  
Energy Excitation ◽  
Illumination Time ◽  
P Type

ABSTRACTThe mechanism of light-induced reactivation (LIR) of shallow substitutional acceptors in high-purity p-type hydrogenated GaAs has been investigated. Photoluminescence was used to determine the dependence of the rate and extent of this effect on photon energy, illumination intensity, as well as on sample temperature and chemical composition. At a sample temperature of 1.7 K a sharp threshold in the photon energy, Et, has been observed at about 7.5 meV below the bandgap energy of GaAs. This energy corresponds approximately to the onset of acceptorbound exciton absorption in the material. For photon energy E < Et, only a weak reactivation effect is observed. The efficiency of reactivation increases dramatically for E > Et, and for sufficiently large values of (light intensity).(illumination time) product the LIR process saturates. Both the extent of the subthreshold effect and the saturation level that is attainable with E > Et are independent of the photon energy, excitation power and exposure time in the investigated range of these quantities. For E > Et the initial LIR rate depends on the square of the light intensity, indicating a bimolecular reaction in terms of the photo-generated carrier densities. The observed strong dependence of the saturation level on the sample temperature during LIR is found to be consistent with the relative binding energies of different acceptor-hydrogen passivating complexes in GaAs. Based on these results, it is proposed that LIR of acceptors is electronically stimulated via recombination-enhanced vibrational excitation of acceptor-hydrogen complexes.

The photolysis of ethylene at 193 nm

1989 ◽  
Vol 67 (7) ◽  
pp. 1166-1173 ◽  
Author(s):  
L. Giroux ◽  
M. H. Back ◽  
R. A. Back
Keyword(s):  
Reaction Time ◽  
Excited States ◽  
Excimer Laser ◽  
Pressure Dependence ◽  
Quantum Yields ◽  
Reaction Products ◽  
Vibrationally Excited ◽  
Uv Photolysis ◽  
Arf Excimer Laser ◽  
193 Nm

The photolysis of ethylene has been studied at pressures from 50 to 3000 Torr using a pulsed ArF excimer laser at 193.3 nm. Major products were acetylene, n-butane, 1-butene, ethane, and 1,3-butadiene, with smaller amounts of propane, propene, methane, and allene. Quantum yields varied with pressure and reaction time; the latter dependence is ascribed to secondary photolysis of butene and butadiene. The reaction products are accounted for by three primary processes:[Formula: see text]followed by reactions of H, [Formula: see text] and C2H5 radicals. The vibrationally excited C2H3radical can decompose to H + C2H2 or can be stabilized by collision. The pressure dependence of the quantum yields of the primary processes [1]–[3] is complex, and a photodissociation mechanism involving several intermediates and excited states of ethylene is presented to account for the present results and previous measurements at 185 nm. Keywords: ethylene, uv photolysis.

Fine structure of the retina of the giant scallop, Placopecten magellanicus

1984 ◽  
Vol 42 ◽  
pp. 312-313
Author(s):  
C.V.L. Powell
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Light Intensity ◽  
Scanning Electron Microscope ◽  
Eye Development ◽  
Preliminary Observation ◽  
Columnar Epithelium ◽  
Placopecten Magellanicus ◽  
Environmental Light ◽  
Scanning Electron

The overall fine structure of the eye in Placopecten is similar to that of other scallops. The optic tentacle consists of an outer columnar epithelium which is modified into a pigmented iris and a cornea (Fig. 1). This capsule encloses the cellular lens, retina, reflecting argentea and the pigmented tapetum. The retina is divided into two parts (Fig. 2). The distal retina functions in the detection of movement and the proximal retina monitors environmental light intensity. The purpose of the present study is to describe the ultrastructure of the retina as a preliminary observation on eye development. This is also the first known presentation of scanning electron microscope studies of the eye of the scallop.

Effect of light intensity on the ultrastructure of the filamentous cyanobacterium, Anabaena variabilis

1988 ◽  
Vol 46 ◽  
pp. 300-301
Author(s):  
C. S. Bricker ◽  
S. R. Barnum ◽  
B. Huang ◽  
J. G. Jaworskl
Keyword(s):  
Fatty Acid ◽  
Light Intensity ◽  
Acid Content ◽  
Fatty Acid Content ◽  
Anabaena Variabilis ◽  
Chloroplast Envelope ◽  
Major Constituent ◽  
Filamentous Cyanobacterium ◽  
Photosynthetic Membrane ◽  
Effect Of Light

Cyanobacteria are Gram negative prokaryotes that are capable of oxygenic photosynthesis. Although there are many similarities between eukaryotes and cyanobacteria in electron transfer and phosphorylation during photosynthesis, there are two features of the photosynthetic apparatus in cyanobacteria which distinguishes them from plants. Cyanobacteria contain phycobiliproteins organized in phycobilisomes on the surface of photosynthetic membrane. Another difference is in the organization of the photosynthetic membranes. Instead of stacked thylakolds within a chloroplast envelope membrane, as seen In eukaryotes, IntracytopIasmlc membranes generally are arranged in three to six concentric layers. Environmental factors such as temperature, nutrition and light fluency can significantly affect the physiology and morphology of cells. The effect of light Intensity shifts on the ultrastructure of Internal membrane in Anabaena variabilis grown under controlled environmental conditions was examined. Since a major constituent of cyanobacterial thylakolds are lipids, the fatty acid content also was measured and correlated with uItrastructural changes. The regulation of fatty acid synthesis in cyanobacteria ultimately can be studied if the fatty acid content can be manipulated.

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