A spectroscopic study of HCP, the phosphorus analogue of hydrocyanic acid

1969 ◽  
Vol 47 (8) ◽  
pp. 893-920 ◽  
Author(s):  
J. W. C. Johns ◽  
H. F. Shurvell ◽  
J. K. Tyler
Keyword(s):  
Energy Levels ◽  
Hydrocyanic Acid ◽  
Ultraviolet Absorption Spectrum ◽  
Triplet States ◽  
Fundamental Vibration ◽  
Excited Triplet ◽  
Singlet States ◽  
State Formula ◽  
Excited Singlet States ◽  
Vibration Rotation

The ultraviolet absorption spectrum of HCP has been observed from 4100 Å to about 2350 Å, and seven electronic transitions have been identified. Three of these transitions involve excited singlet states and four of them involve excited triplet states. The symmetries, energies, and equilibrium conformations of these states are listed below:[Formula: see text]Some observations have also been made on the vibration–rotation energy levels of the ground electronic state, [Formula: see text], of HCP. The fundamental vibration frequencies (in cm−1) are ν1 = 3216.9, ν2 = 674.7, and ν3 = 1278.4.

Effect of cyclodextrin complexation on the photochemistry of the lignin model α-guaiacoxyacetoveratrone

1999 ◽  
Vol 77 (8) ◽  
pp. 1356-1365 ◽  
Author(s):  
L T Okano ◽  
R Ovans ◽  
V Zunic ◽  
J N Moorthy ◽  
C Bohne
Keyword(s):  
Fluorescence Emission ◽  
Qualitative Behavior ◽  
Triplet States ◽  
Solvated Electrons ◽  
Excited Triplet ◽  
Fluorescence Studies ◽  
Singlet States ◽  
Lignin Model ◽  
Excited Singlet States

The photodecomposition of α-guaiacoxyacetoveratrone (GAV) in homogeneous solvents and in aqueous cyclodextrin solutions was studied by following the fluorescence emission of the photoproducts formed. The same qualitative behavior as previously observed for the photodegradation quantum yield measurements was reproduced in the fluorescence studies in dry or wet methanol and acetonitrile. The yield for GAV photodegradation in water is smaller than in the organic solvents. Complexation of GAV to β- and γ-cyclodextrins leads to an increase in the photodecomposition yield, especially during the early part of the photodecomposition kinetics. The transients formed in the photolysis of GAV in water are similar to those observed in acetonitrile, and the lifetime of triplet GAV in water is 130 ns. In addition, solvated electrons were formed when GAV was photolyzed in water. Complexation of GAV to cyclodextrins leads to an increase in the triplet yield compared to the radical yield and a moderate shortening of the triplet lifetime.Key words: α-guaiacoxyacetoveratrone, cyclodextrin, excited singlet states, excited triplet states, radicals.

Fluorene-Type Polymer Photodetectors Doped with Iridium and Platinum Complexes as Opto-Electrical Conversion Devices

2012 ◽  
Vol 1435 ◽  
Author(s):  
Hirotake Kajii ◽  
Hiroki Ohmori ◽  
Yusuke Sato ◽  
Akihiro Katsura ◽  
Yutaka Ohmori
Keyword(s):  
Conversion Efficiency ◽  
Solution Process ◽  
Platinum Complexes ◽  
Triplet States ◽  
Excited Singlet ◽  
Excited Triplet ◽  
Optical Links ◽  
Singlet States ◽  
Excited Singlet States ◽  
Excited Triplet States

ABSTRACTTo improve the conversion efficiency of polymer photodetectors (PDs) fabricated by solution process, the properties of fluorene-type polymer photodetectors doped with iridium (Ir) and platinum (Pt) complexes were investigated. The devices based on poly(dioctylfluorene) and poly(dioctylfluorene-co-benzothiadiazole) (F8BT) had violet and blue sensitivity, respectively. Triplet materials can enhance the incident-photon-to-current conversion efficiency of the devices utilizing the fluorene-type polymers when their triplet levels are lower than the lowest excited singlet states of the host and higher than the lowest excited triplet states of the host. The transmission of a moving picture was successfully demonstrated using the bilayer F8BT device with green Ir complex as an opto-electrical conversion device. We demonstrate that the polymer PDs fabricated by solution process can be applied to short-range optical communication fields, such as opto-electrical conversion devices for optical links.

Nanosecond flash photolysis

1970 ◽  
Vol 315 (1521) ◽  
pp. 163-184 ◽  
Keyword(s):  
Flash Photolysis ◽  
Pulsed Laser ◽  
Triplet States ◽  
Excited Singlet ◽  
Excited Triplet ◽  
Singlet States ◽  
Time Region ◽  
Excited Singlet States ◽  
Chemical Events ◽  
Excited Triplet States

A flash photolysis system, using a pulsed laser as source, has been designed and used to study events having a duration of a few nanoseconds; an improvement over conventional flash techniques by a factor of a thousand. The apparatus incorporates both spectrographic and photoelectric monitoring techniques which are easily interchangeable and, apart from the laser itself, it is readily constructed from standard components. Its applications to the observation of the absorption spectra of excited singlet states, short-lived excited triplet states and chemical events in the nanosecond time region are described.

Energy Levels of Oligothiophenes in the Higher Excited Triplet States

2007 ◽  
Vol 111 (2) ◽  
pp. 1024-1028 ◽  
Author(s):  
Yosuke Oseki ◽  
Mamoru Fujitsuka ◽  
Masanori Sakamoto ◽  
Xichen Cai ◽  
Tetsuro Majima
Keyword(s):  
Energy Levels ◽  
Triplet States ◽  
Excited Triplet ◽  
Excited Triplet States

A vibration-rotation band of monodeuteromethane

1953 ◽  
Vol 216 (1125) ◽  
pp. 143-152 ◽  
Keyword(s):  
Energy Levels ◽  
High Dispersion ◽  
Vibration Band ◽  
Hydrogen Atoms ◽  
Vibrational States ◽  
Fundamental Vibration ◽  
Type Band ◽  
Vibration Rotation ◽  
Two Sides ◽  
Very High

The fundamental vibration band of monodeuteromethane near 4-5 μ , connected with the stretching of the C—D bond, has been reinvestigated with very high dispersion. It provides a good example of well-resolved parallel-type band structure of a symmetric top molecule in which the K splitting of P and R lines is clearly seen. Alternations of intensity are also found in accordance with the nuclear spin of the three hydrogen atoms. The rotational constants B 0 and B 1 have been determined, giving r 0 (C—H) = 1.0924Å. The centrifugal stretching coefficient D J and its variation in the different vibrational states have also been measured. Analysis of the K splitting of the R and P lines reveals an anomaly between the sets on the two sides of the band origin, which seems to suggest that some unforeseen molecular interaction is neglected in the method at present accepted for calculating the molecular rotational energy levels.

scholarly journals Theoretical Analysis of the Effect Provoked by Bromine-Addition on the Thermolysis and Chemiexcitation of a Model Dioxetanone

2017 ◽  
Vol 2017 ◽  
pp. 1-8
Author(s):  
Luís Pinto da Silva ◽  
Rui F. J. Pereira ◽  
Joaquim C. G. Esteves da Silva
Keyword(s):  
Light Emission ◽  
Heavy Atom ◽  
Quantum Yields ◽  
Efficient Production ◽  
Triplet States ◽  
Singlet States ◽  
Electronically Excited ◽  
Excited Singlet States ◽  
Thermolysis Reaction ◽  
Effect Of Heavy Atom

Chemi-/bioluminescence are phenomena in which chemical energy is converted into electronically excited singlet states, which decay with light emission. Given this feature, along with high quantum yields and other beneficial characteristics, these systems have gained numerous applications in bioanalysis, in biomedicine, and in the pharmaceutical field. Singlet chemiexcitation is made possible by the formation of cyclic peroxides (as dioxetanones) as thermolysis provides a route for a ground state reaction to produce singlet excited states. However, such thermolysis can also lead to the formation of triplet states. While triplet states are not desired in the typical applications of chemi-/bioluminescence, the efficient production of such states can open the door for the use of these systems as sensitizers in photocatalysis and triplet-triplet annihilation, among other fields. Thus, the goal of this study is to assess the effect of heavy atom addition on the thermolysis and triplet chemiexcitation of a model dioxetanone. Monobromination does not affect the thermolysis reaction but can improve the efficiency of intersystem crossing, depending on the position of monobromination. Addition of bromine atoms to the triplet state reaction product has little effect on its properties, except on its electron affinity, in which monobromination can increase between 3.1 and 8.8 kcal mol−1.

Photolysis of SO2 in the Presence of Foreign Gases. VI. Acetylene and Allene

1974 ◽  
Vol 52 (20) ◽  
pp. 3451-3453 ◽  
Author(s):  
Menachem Luria ◽  
Julian Heicklen
Keyword(s):  
Triplet State ◽  
Gas Phase ◽  
Triplet States ◽  
Relative Importance ◽  
Excited Singlet ◽  
Singlet States ◽  
Excited Singlet States ◽  
Allene System

The photolysis of SO2 at 3130 Å and 25 °C in the presence of C2H2 leads to CO, and, in the presence of allene to CO and C2H4 as gas phase products. In the C2H2 system, the CO comes from the two non-emitting triplet states of SO2, 57% from SO2** and 43% from SO2≠. In the allene system, the two excited singlet states of SO2, and possibly the emitting triplet state, also participate. The relative importance of the contributions from each state can be estimated to be >35% from 1SO2, <16% from 3SO2, 8% from SO2*, 12% from SO2**, and 29% from SO2≠.

Electronic absorption spectrum of nickel(II) in cubic perovskite fluorides. III. The ultraviolet spectrum

1968 ◽  
Vol 21 (2) ◽  
pp. 323 ◽  
Author(s):  
J Ferguson
Keyword(s):  
Absorption Spectrum ◽  
Ultraviolet Absorption ◽  
Ultraviolet Absorption Spectrum ◽  
Electronic Excitations ◽  
Absorption Bands ◽  
Nickel Ion ◽  
Nickel Ions ◽  
Singlet States ◽  
Divalent Nickel ◽  
Excited Singlet States

The ultraviolet absorption spectrum of divalent nickel is shown to be dependent on concentration for crystals of composition KMgxNil-xF3 with 0 < x < 1. The eight ultraviolet absorption bands have intensities which are directly related to the number of nearest neighbour nickel ions per nickel ion. Three of the bands can be assigned to states of the 1G and 1S terms while the remaining five have energies which can be equated to combinations of the energies of the excited singlet states lEga ITa2g and 1Aag and are simultaneous electronic excitations.

Zusammenhang zwischen Schweratominduzierter Fluoreszenzlöschung und Termschema von mehrkernigen aromatischen Kohlenwasserstoffen / Correlation between Heavy-atom induced Fluorescence Quenching and Energy Levels of Polynuclear Aromatic Hydrocarbons

1973 ◽  
Vol 28 (10) ◽  
pp. 1743-1744
Author(s):  
H. Dreeskamp ◽  
M. Zander
Keyword(s):  
Aromatic Hydrocarbons ◽  
Energy Gap ◽  
Energy Levels ◽  
Heavy Atom ◽  
Polynuclear Aromatic Hydrocarbons ◽  
Intersystem Crossing ◽  
Triplet States ◽  
Excited Triplet ◽  
Wide Energy ◽  
Excited Triplet States

The observation that the fluorescence of certain polynuclear aromatic hydrocarbons (perylene, 1.2 ;5.6-dibenzoperylene, 9.10-diphenylanthracene and rubrene) is quenched by alkyl iodides only slightly is explained on the basis of the energy levels of these hydrocarbons. In these systems an effective radiationless desactivation of the fluorescing state S1 by intersystem crossing into the triplet manifold is prevented by a wide energy gap between S1 and the lowest triplet state, and the absence of excited triplet states below s,.

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