DIFFUSENESS IN ELECTRONIC SPECTRA THE VAPOR SPECTRUM OF ANTHRACENE

1965 ◽  
Vol 43 (12) ◽  
pp. 3253-3257 ◽  
Author(s):  
J. P. Byrne ◽  
I. G. Ross
Keyword(s):  
Electronic Spectra ◽  
Room Temperature ◽  
Sequence Structure ◽  
Short Region ◽  
Sharp Structure ◽  
Singlet Transition

Approximate calculations of the number of rovibronic transitions per unit wavenumber are given for benzene, naphthalene, anthracene, and tetracene. Primarily because of the density of sequence structure all transitions in tetracene vapor should be irresolvably crowded, and hence apparently diffuse, at practical temperatures. Anthracene, whose spectrum has hitherto been described as wholly diffuse, is predicted to be capable of showing resolvable structure at room temperature. At 60 °C and 40 m path a short region of fine sharp structure has been observed. The origin of the first singlet transition is located at 27 688.3 cm−1 (27 757.6 cm−1 in anthracene-d10).

Copper(II) Dihydroxybenzoates; Synthesis and Properties

1993 ◽  
Vol 58 (6) ◽  
pp. 1363-1370 ◽  
Author(s):  
Jozef Sokolík ◽  
Brigita Lučanská ◽  
Gustáv Plesch ◽  
Ingrid Tumová ◽  
Aladár Valent ◽  
...  
Keyword(s):  
Carboxylic Acids ◽  
Electronic Spectra ◽  
Room Temperature ◽  
Magnetic Moments ◽  
Tetragonal Distortion ◽  
High Toxicity ◽  
Antipyretic Activity ◽  
Pharmacological Screening ◽  
Cooperative Ordering

Compounds of composition Cu(2,5-DHB)2 . 4 H2O (DHB, dihydroxybenoate anion) and Cu(2,Y-DHB)2 . 8 H2O (Y = 4 or 6) were prepared as potential antiinflamatory gents with a view of pharmacological screening. The room-temperature magnetic moments allow to classify all compounds into the group of magnetically diluted copper(II) complexes. According the EPR and electronic spectra, the degree of tetragonal distortion increases passing from Cu(2,6-DHB)2 . 8 H2O (III) through Cu(2,4-DHB)2 . 8 H2O (I) to Cu(2,5-DHB)2 . 4 H2O (II. The complexes differ also in the cooperative ordering in their structures. All tested compounds exhibit higher antiinflamatory activities (on dextran edema) than free carboxylic acids. However, their effects were accompanied with relatively high toxicity. Remarkable results were also achieved on evaluating the antipyretic activity.

Electronic spectra of dibenzo[a,d]cycloheptatrienylidene at 77°K and room temperature

Tetrahedron ◽  
1970 ◽  
Vol 26 (1) ◽  
pp. 251-254 ◽  
Author(s):  
Y. Yamamoto ◽  
I. Moritani ◽  
Y. Maeda ◽  
S. Murahashi
Keyword(s):  
Electronic Spectra ◽  
Room Temperature

Cooperative Spin Transitions in Iron(II) Derivatives of 1,2,4-Triazole

1994 ◽  
Vol 47 (2) ◽  
pp. 263 ◽  
Author(s):  
KH Sugiyarto ◽  
HA Goodwin
Keyword(s):  
Hysteresis Loop ◽  
Temperature Dependence ◽  
Transition Region ◽  
Electronic Spectra ◽  
Room Temperature ◽  
Coordination Core ◽  
Continuous Transition ◽  
Quintet State ◽  
Derivatives Of ◽  
Perchlorate Salt

Complexes of stoichiometry Fe( trzH )2( trz )X, where trzH is 1,2,4-triazole and X = BF4, ClO4, PF6, have been prepared. All three salts display temperature-induced singlet (1A1) ↔ quintet (5T2) transitions which are generally discontinuous and associated with a broad hysteresis loop. The salts are strongly thermochromic, being white above and pink-lilac below the transition region. Several samples of each salt were obtained and the detailed behaviour varied somewhat from one sample to another. For the fluoroborate and perchlorate salts the transition is centred above room temperature while for the hexafluorophosphate salt it occurs below room temperature. The perchlorate salt was also isolated in a form which showed a continuous transition but the nature of its electronic properties changed as the sample aged. In one form of the hexafluorophosphate salt the hysteresis loop spans room temperature and it has been possible to characterize both the singlet and the quintet state species at that temperature. For all three salts the transition has been characterized by measurement of the temperature dependence of the magnetism and Mossbauer and electronic spectra. These measurements establish that the complexes all contain an FeN6 coordination core and this must be achieved through bridging of the triazole units.

Room-Temperature Coherent Optical Phonon in 2D Electronic Spectra of CH3NH3PbI3 Perovskite as a Possible Cooling Bottleneck

2017 ◽  
Vol 8 (14) ◽  
pp. 3211-3215 ◽  
Author(s):  
Daniele M. Monahan ◽  
Liang Guo ◽  
Jia Lin ◽  
Letian Dou ◽  
Peidong Yang ◽  
...  
Keyword(s):  
Optical Phonon ◽  
Electronic Spectra ◽  
Room Temperature

Spectroscopic studies on toluene and some deuterated derivatives. II. Electronic spectra

1994 ◽  
Vol 72 (11-12) ◽  
pp. 1225-1235 ◽  
Author(s):  
Walter J. Balfour ◽  
Ram S. Ram
Keyword(s):  
Excited State ◽  
High Resolution ◽  
Ground State ◽  
Electronic Spectra ◽  
Spectroscopic Studies ◽  
Measured Data ◽  
Sequence Structure ◽  
State Information ◽  
Isotopic Species ◽  
Out Of Plane

The 266.7 nm absorption systems of toluene and seven deuterated isomers were observed at high resolution and analyses of their vibronic structure performed. All in-plane vibrations with ground-state frequencies less than 1000 cm−1 were identified from 0–1 hot bands. The frequencies agree well with data obtained from infrared and Raman studies. The corresponding vibrations were identified in the excited state. Information was also obtained on out-of-plane vibrations with ground-state frequencies less than 650 cm−1, since all of these are found to give sequence structure. A comparison of the measured data for the various isotopic species has enabled a consistent description of the excited state in toluene to be made. Problems associated with errors, ambiguities, and inconsistencies in previously published work have been addressed.

Dependence of Intergranular Fracture on Boundary Topography and Cohesion

1973 ◽  
Vol 31 ◽  
pp. 150-151
Author(s):  
J. E. Doherty ◽  
A. F. Giamei ◽  
B. H. Kear ◽  
C. W. Steinke
Keyword(s):  
Grain Boundary ◽  
Room Temperature ◽  
Nickel Base Superalloy ◽  
Boundary Shear ◽  
Room Temperature Ductility ◽  
Solid Solution Matrix ◽  
Nickel Base ◽  
Solution Matrix ◽  
Different Levels ◽  
Base Superalloy

Recently we have been investigating a class of nickel-base superalloys which possess substantial room temperature ductility. This improvement in ductility is directly related to improvements in grain boundary strength due to increased boundary cohesion through control of detrimental impurities and improved boundary shear strength by controlled grain boundary micros true tures.For these investigations an experimental nickel-base superalloy was doped with different levels of sulphur impurity. The micros tructure after a heat treatment of 1360°C for 2 hr, 1200°C for 16 hr consists of coherent precipitates of γ’ Ni3(Al,X) in a nickel solid solution matrix.

Hepatocyte Alterations in Guinea Pigs FED Polychlorinated Biphenyls (PCBs), Dibenzodioxins (PCDD), AND DIBENZOFURANS (PCDF)

1982 ◽  
Vol 40 ◽  
pp. 56-57
Author(s):  
J. N. Turner ◽  
D. N. Collins
Keyword(s):  
Guinea Pigs ◽  
Room Temperature ◽  
Dose Group ◽  
Methyl Cellulose ◽  
Uranyl Acetate ◽  
Target Organ ◽  
Office Building ◽  
Lead Citrate ◽  
Control Groups ◽  
Cooling Fluid

A fire involving an electric service transformer and its cooling fluid, a mixture of PCBs and chlorinated benzenes, contaminated an office building with a fine soot. Chemical analysis showed PCDDs and PCDFs including the highly toxic tetra isomers. Guinea pigs were chosen as an experimental animal to test the soot's toxicity because of their sensitivity to these compounds, and the liver was examined because it is a target organ. The soot was suspended in 0.75% methyl cellulose and administered in a single dose by gavage at levels of 1,10,100, and 500mgm soot/kgm body weight. Each dose group was composed of 6 males and 6 females. Control groups included 12 (6 male, 6 female) animals fed activated carbon in methyl cellulose, 6 males fed methyl cellulose, and 16 males and 10 females untreated. The guinea pigs were sacrificed at 42 days by suffocation in CO2. Liver samples were immediately immersed and minced in 2% gluteraldehyde in cacadylate buffer at pH 7.4 and 4°C. After overnight fixation, samples were postfixed in 1% OsO4 in cacodylate for 1 hr at room temperature, embedded in epon, sectioned and stained with uranyl acetate and lead citrate.

Domain Formation in Synthetic Quartz

1971 ◽  
Vol 29 ◽  
pp. 156-157
Author(s):  
Joseph J. Comer
Keyword(s):  
Electron Beam ◽  
Room Temperature ◽  
Domain Formation ◽  
Synthetic Quartz ◽  
Transmission Electron ◽  
Black Spots ◽  
Diffraction Mode ◽  
Domain Boundaries ◽  
Kikuchi Lines ◽  
Straight Lines

Domains visible by transmission electron microscopy, believed to be Dauphiné inversion twins, were found in some specimens of synthetic quartz heated to 680°C and cooled to room temperature. With the electron beam close to parallel to the [0001] direction the domain boundaries appeared as straight lines normal to <100> and <410> or <510> directions. In the selected area diffraction mode, a shift of the Kikuchi lines was observed when the electron beam was made to traverse the specimen across a boundary. This shift indicates a change in orientation which accounts for the visibility of the domain by diffraction contrast when the specimen is tilted. Upon exposure to a 100 KV electron beam with a flux of 5x 1018 electrons/cm2sec the boundaries are rapidly decorated by radiation damage centers appearing as black spots. Similar crystallographio boundaries were sometimes found in unannealed (0001) quartz damaged by electrons.

A Liquid Nitrogen Cooled Stage for STEM

1974 ◽  
Vol 32 ◽  
pp. 444-445
Author(s):  
Louis T. Germinario
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Liquid Nitrogen ◽  
Room Temperature ◽  
Objective Lens ◽  
Thermal Drift ◽  
Specimen Holder ◽  
Resolution Capability ◽  
Focal Position

A liquid nitrogen stage has been developed for the JEOL JEM-100B electron microscope equipped with a scanning attachment. The design is a modification of the standard JEM-100B SEM specimen holder with specimen cooling to any temperatures In the range ~ 55°K to room temperature. Since the specimen plane is maintained at the ‘high resolution’ focal position of the objective lens and ‘bumping’ and thermal drift la minimized by supercooling the liquid nitrogen, the high resolution capability of the microscope is maintained (Fig.4).

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