The absorption spectrum of KBr:Sn2+

1982 ◽  
Vol 60 (5) ◽  
pp. 619-627 ◽  
Author(s):  
A. Scacco ◽  
P. W. M. Jacobs
Keyword(s):  
Absorption Spectrum ◽  
Theoretical Model ◽  
Absorption Spectra ◽  
Cation Vacancy ◽  
Relative Concentration ◽  
Hamiltonian Matrix ◽  
Absorption Bands ◽  
Different Types ◽  
Experimental Absorption ◽  
Good Agreement

Thorough annealing on crystals of KBr.Sn2+ results in significant changes in their absorption spectra. These changes have been interpreted as the effect of the annealing on the relative concentration of different types of Sn2+ centres: isolated Sn2+ substitutional ions ("cubic" centres) and Sn2+–cation vacancy complexes ("tetragonal" and "rhombic" centres). The line shape of the optical absorption has been calculated theoretically, by diagonalizing the complete 12 × 12 Hamiltonian matrix, for cubic centres only, for tetragonal centres only, and for different relative concentrations of cubic and tetragonal centres. The experimental absorption spectra of KBr:Sn2+ crystals that have undergone various annealing treatments are in good agreement with theoretical spectra calculated for appropriate mixtures of the above centres. These results confirm that thorough annealing increases the fraction of isolated Sn2+ substitutional ions at the expense of the Sn2+–cation vacancy complexes. The consistency of the theoretical model is demonstrated by the agreement of the calculated moments of the absorption bands of KBr:Sn2+ with the experimentally derived values.

The A2Πi–X2Πi absorption spectrum of BrO

1981 ◽  
Vol 59 (12) ◽  
pp. 1908-1916 ◽  
Author(s):  
M. Barnett ◽  
E. A. Cohen ◽  
D. A. Ramsay
Keyword(s):  
Absorption Spectrum ◽  
Absorption Spectra ◽  
Ground State ◽  
Flash Photolysis ◽  
Absorption Bands ◽  
Long Wavelength ◽  
Numbering Scheme ◽  
Ozonized Oxygen ◽  
Good Agreement

Absorption spectra of isotopically enriched 81Br16O and of normal BrO have been obtained by the flash photolysis of mixtures of bromine and ozonized oxygen. Rotational analyses are given for the 7–0, 12–0, 18–0, 19–0, 20–0, 21–0, 7–1, and 20–1 A2Π3/2–X2Π3/2 sub-bands of 81Br16O. The value for [Formula: see text] is found to be 722.1 ± 1.1 cm−1 in good agreement with the value calculated from microwave constants. Several additional bands have been found at the long wavelength end of the spectrum, necessitating a revision of the vibrational numbering scheme for both the emission and absorption bands. "Hot" bands up to ν″ = 6 have been observed in the absorption spectrum for the 2Π3/2 component of the ground state but no bands have yet been identified from the 2Π1/2 component.

scholarly journals The absorption spectra of halogens and inter-halogen compounds in solution in carbon tetrachloride

1929 ◽  
Vol 124 (795) ◽  
pp. 604-616 ◽  
Keyword(s):  
Absorption Spectrum ◽  
Carbon Tetrachloride ◽  
Absorption Spectra ◽  
Spectroscopic Data ◽  
Chemical Interaction ◽  
Chemical Compounds ◽  
Absorption Bands ◽  
Halogen Compounds ◽  
Inert Solvent ◽  
The Mean

When two solutions are mixed the absorption spectrum of the new solution will be the mean of those of the separate solutions provided that no chemical interaction occures. The mere fact of a departure from additivity does not, however, necessarily denote the formation of true chemical compounds. The solute or solutes may undergo solvation, loosely bound aggregates may occur, and even when marked deviations from the simple law of mixtures are observed it is rarely possible to prove the quantitative formation of a given chemical compound from spectroscopic data alone. The above considerations apply with some force to the problem of the absorption spectra of halogens and inter-halogen compounds in an inert solvent. The three elements show perfectly characteristic absorption bands, they are known to interact with the formation of some quite stable compounds, some relatively stable compounds, and some apparently very unstable compounds.

scholarly journals The absorption spectra of conjugated dienes in the vacuum ultra-violet (1)

1940 ◽  
Vol 174 (957) ◽  
pp. 220-234 ◽  
Keyword(s):  
Absorption Spectrum ◽  
Absorption Spectra ◽  
Electronic Structures ◽  
Spectroscopic Data ◽  
Ultra Violet ◽  
Conjugated Dienes ◽  
Strong Absorption ◽  
Absorption Bands ◽  
Lennard Jones ◽  
Vacuum Ultra Violet

Butadiene is important as the simplest example of resonance between two conjugated double bonds. The comparison of its ultra-violet absorption spectrum with that of ethylene might be expected to give some indication of the way the π electrons of the molecule are affected by the resonance. The electronic structures of a number of molecules for which resonance is important have been worked out theoretically by Hückel (1935), Lennard- Jones (1937), Sklar (1937) and Mulliken (1939 a and b ). The purpose of the present work is to obtain spectroscopic data with which the theoretical expectations can be compared. As most of the strong absorption bands of these molecules occur at wave-lengths less than 2000 A, the investigation falls naturally into the region of vacuum spectroscopy.

Spectroelectrochemical Study of some μ3-Oxo-μ-acetato Trinuclear Rhodium(III) and Iridium(III) Complexes

1995 ◽  
Vol 50 (4) ◽  
pp. 551-557 ◽  
Author(s):  
Kenta Takahashi ◽  
Keisuke Umakoshi ◽  
Akihiro Kikuchi ◽  
Yoichi Sasaki ◽  
Masato Tominaga ◽  
...  
Keyword(s):  
Absorption Spectrum ◽  
Electronic Absorption Spectrum ◽  
Absorption Spectra ◽  
Electronic Absorption ◽  
Electronic Absorption Spectra ◽  
Visible Region ◽  
Absorption Bands ◽  
Visible Absorption ◽  
The One ◽  
Species Being

New trinuclear rhodium(III) complexes, [Rh3(μ3-O)(μ-CH3COO)6(L)3]+ (L = imidazole (Him), 1-methylimidazole (Meim), and 4-methylpyridine (Mepy)) have been prepared. The Him, Meim, and Mepy complexes show reversible one-electron oxidation waves at E1/2 = +1.12, +1.12, and +1.28 V vs Ag/AgCl, respectively, in acetonitrile. Electronic absorption spectra of the one electron oxidized species of these complexes and [Rh3(μ3-O)(μ-CH3COO)6(py)3]+ (py = pyridine) (E1/2 = +1.32 V ) were obtained by spectroelectrochemical techniques. While the Rh3(III,III,III) states show no strong visible absorption, the Rh3(III,III,IV ) species give a band at ca. 700 nm (ε = 3390-5540 mol dm-3 cm-1). [Ir3(μ3-O)(μ-CH3COO)6(py)3]+ with no strong absorption in the visible region, shows two reversible one-electron oxidation waves at +0.68 and +1.86 V in acetonitrile. The electronic absorption spectrum of the one-electron oxidized species (Ir3(III,III,IV )) also shows some absorption bands (688 nm (ε, 5119), 1093 (2325) and 1400 (ca. 1800)). It is suggested that the oxidation removes an electron from the fully occupied anti-bonding orbital based on metal-dπ-μ3-O-pπ interactions, the absorption bands of the (III,III,IV ) species being assigned to transitions to the anti-bonding orbital.

Optical properties of arsenic trisulphide

1967 ◽  
Vol 297 (1449) ◽  
pp. 230-243 ◽  
Keyword(s):  
Optical Properties ◽  
Absorption Spectrum ◽  
High Energy ◽  
Refractive Indices ◽  
Optical Absorption Spectra ◽  
Absorption Bands ◽  
Axial Angle ◽  
Transmission Measurements ◽  
Additional Maximum ◽  
Good Agreement

The optical absorption spectra ( E || c , E ⊥ c ) of As 2 S 3 have been determined from transmission measurements on single crystals ranging in thickness from 550 to 0·07 μm, At 77 °K the absorption spectrum ( E || c ) consists of three absorption bands A, B and C at 23300, 24100 and 25600 cm -1 respectively. The absorption bands for E ⊥ c occur 500 cm -1 to the high energy side of those for E || c . The variation of absorption coefficient α with photon energy hv at the absorption edge (290°K) can be resolved into four regions each of which is described by the equation α = a ( hv + b ) 2 . At 290 and 77°K the single crystal reflexion spectra ( E || c , E ⊥ c ) show maxima associated with the absorption bands and an additional maximum at 35000 cm -1 . The calculated and measured reflectivities are in good agreement. Measurements have been made of the dispersion of the principal refractive indices and of the optic axial angle. The spectral distribution of photocurrent shows peaks associated with absorption bands B and C ( E || c , E ⊥ c ).

scholarly journals IV. On the absorption-spectra of bromine and iodine monochloride

1877 ◽  
Vol 25 (171-178) ◽  
pp. 4-4
Keyword(s):  
Absorption Spectrum ◽  
Absorption Spectra ◽  
Graphical Method ◽  
Wave Length ◽  
Iodine Monochloride ◽  
Absorption Bands ◽  
General Applicability ◽  
Molecular Weights

The paper contains the results of an exact series of measurements of the absorption-spectra of the vapours of the element bromine and of the compound iodine monochloride, made with the object of ascertaining whether the molecules of these two gases vibrate identically or similarly, their molecular weights and colour of the vapours being almost identical. The two spectra, which are both channelled, were compared simultaneously by means of one of Kirchhoff’s 4-prism spectroscopes, the position of the lines being read off by reflection on an arbitrary scale. In order to determine the wave-lengths of these bands, the wave-length of each of 27 air-lines lying between the extremes of the absorption-spectra was ascertained by reference to Thalén’s numbers; whilst for the purpose of reducing the readings of the absorption-bands to wave-lengths a graphical method was employed, the details of which are given in the paper. This method appears to be one of general applicability for the plotting of spectra. Tables then follow giving the wave-lengths of 66 bands of each absorption-spectrum; and a map accompanies the text in which the bands are drawn to a scale one half that of Ångström’s “Spectre Normal.”

Zur Elektronenstruktur metallorganischer Komplexe der f-Elemente, IV Zuordnung der Absorptionsbanden im Raumtemperatur-Absorptionsspektrum von Tris-(cyclopentadienyl)-uran(IV)-tetrahydroborat / The Electronic Structure of Organometallic Complexes Involving f-Electrons, IV Assignment of the Absorption Bands in the Room Temperature Absorption Spectrum of Tris-(cyclopentadienide)-uran(IV)-borohydride

1976 ◽  
Vol 31 (6) ◽  
pp. 769-773 ◽  
Author(s):  
H.-D. Ambergeb ◽  
G. R. Sienel
Keyword(s):  
Absorption Spectrum ◽  
Electronic Structure ◽  
Room Temperature ◽  
Organometallic Complexes ◽  
Energy Matrix ◽  
Absorption Bands ◽  
Complete Energy Matrix ◽  
Room Temperature Absorption Spectrum ◽  
Good Agreement

The bands of the room temperature absorption spectrum of (C5H5)3U(IV)BH4 have been identified on the basis of the complete energy matrix of the tetrahedral f2-system. Using the parameter set: F2 = 181, F4 = 33.5, F6 = 3.8, ζ5f = 1815, B4° = —495 and B6° = —292 cm-1 a good agreement between observed and calculated signals has been achieved.

scholarly journals On the fluorescence and channelled absorption spectra of cæsium and other alkali elements

1923 ◽  
Vol 103 (721) ◽  
pp. 304-314 ◽  
Keyword(s):  
Absorption Spectrum ◽  
Fluorescence Spectrum ◽  
Absorption Spectra ◽  
Wave Length ◽  
Monochromatic Light ◽  
Exciting Light ◽  
Absorption Bands ◽  
The Mean ◽  
Alkali Elements ◽  
Different Sources

In 1874 it was shown by Roscoe and Schuster that channelled absorption spectra can be obtained with the vapours of the alkali elements sodium and potassium, and later on these spectra were investigated in some detail by Liveing and Dewar. It was also shown in 1896 by Weidemann and Schmidt that the vapours of these same metals emitted a radiation possessing characteristics of a fluorescence spectrum when they were traversed by white light. Since 1903 exhaustive studies have been made of both the fluorescence and the channelled absorption spectrum of sodium by R. W. Wood, together with a number of collaborators, Including J. H. Moore and F. E. Hackett. In these investigation it was shown that the channelled absorption spectrum of sodium was made up of a number of series of absorption bands, one set of series being on the red wave-length side of the D lines, and another lying in the visible blue-green region. In addition, series of absorption bands were found by them with approximately regular spacing in the neighbourhood of λ = 3303 A, the second member of the doublet series of this element. As regards the fluorescence spectrum of sodium, they found that, by stimulation of the vapour with approximately monochromatic light, there resulted an emission of light, the spectrum of which consisted of a number of bright but narrow bands of varying intensity, more or less regularly spaced both above and below the mean wave-length of the exciting light. They observed, too, that the slightest change in the wave-length of the exciting light resulted in the disappearance of one set of lines and in the appearance of another of different wave-lengths. In the various florescence spectra obtained by R. W. Wood when stimulating sodium vapour by monochromatic light from different sources, it was noted that there was a remarkable recurrence of the interval, ∆ λ = 52·3 A. in the spacing of the fluorescence bands.

THE ULTRAVIOLET ABSORPTION SPECTRA OF ALIPHATIC NITRAMINES, NITROSAMINES, AND NITRATES

1949 ◽  
Vol 27b (11) ◽  
pp. 828-860 ◽  
Author(s):  
R. Norman Jones ◽  
G. Denis Thorn
Keyword(s):  
Absorption Spectrum ◽  
Absorption Spectra ◽  
Ultraviolet Spectrum ◽  
Ultraviolet Absorption ◽  
Absorption Bands ◽  
Structure Formula ◽  
New Compounds

The ultraviolet absorption bands associated with the following groups have been investigated in a variety of compounds of known structure:[Formula: see text]The groups may be characterized by the ultraviolet spectrum, and the number of each type of group present in a given compound may be estimated from an analysis of the shape and intensity of the absorption spectrum. These correlations have been applied to the elucidation of the structure of new compounds isolated in the course of the investigation of the chemistry of 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX).

scholarly journals Theoretical Study of the Absorption Spectrum and the Thermochemistry of the CF3OSO3 Radical

2010 ◽  
Vol 65 (8-9) ◽  
pp. 720-724 ◽  
Author(s):  
Carlos J. Cobos ◽  
Adela E. Croce
Keyword(s):  
Absorption Spectrum ◽  
Density Functional ◽  
Basis Set ◽  
Absorption Bands ◽  
Visible Absorption ◽  
Functional Theory ◽  
Dissociation Enthalpy ◽  
The Density Functional Theory ◽  
Uv Visible ◽  
Experimental Absorption

The UV-visible absorption spectrum of the recently reported CF3OSO3 radical has been studied by using the time-dependent generalization of the density functional theory (TDDFT). For this a set of eleven hybrid functionals combined with the 6-311+G(3df) basis set were employed. The main features of the three experimental absorption bands of CF3OSO3 recorded over the 220 - 530 nm range are well reproduced by the calculations. A dissociation enthalpy for the CF3O-SO3 bond of 19.1 kcal mol−1 is predicted at the BAC-G3MP2//B3LYP/6-311+G(3df) level of theory

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