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1.
Quasi-line low-temperature (T = 77 and 4.2 K) luminescence spectra of uranyl sulfates and oxalates have been recorded and
analyzed. It has been shown that the spectral structure is determined by the manifestation of the internal and external vibrations
of both the uranyl ion and molecular groups (SO4)2– and (C2O4)2–bonded to the uranyl ion. The spectral line half-width is of the order of ≈5–7 cm–1; the line shape, close to Lorentzian. The fluorescence spectra may be complicated by structural defects in the crystals. 相似文献
2.
Infrared spectra of brassinolide and castasterone steroid phytohormones and their 24-epi derivatives
Absorption bands in IR spectra of brassinolide, castasterone, and their 24-epi derivatives in the frequency range 3800–1000
cm–1 have been interpreted. A number of spectral features distinguishing brassinolide from castasterone have been found. The conducted
analysis shows that the structural differences manifest themselves in IR spectra of the investigated brassinosteroids in the
region of stretching vibrations of CO–H, C=O, C–OH, C–O–C, CH3, CH2, and CH groups. The main distinctions in IR spectra of brassinolides and castasterones are due to the B ring structure. 相似文献
3.
R. M. Vlasova N. V. Drichko O. O. Drozdova R. N. Lyubovskaya 《Physics of the Solid State》1997,39(8):1165-1170
The reflection spectra and optical conductivity spectra of the new organic conductor ϰ-(ET)2[Hg(SCN)2Cl] with a metal-insulator transition in the spectral regions 700–5500 and 9000–40 000 cm−1 have been studied in polarized light at 300 K. A comparisonis made between the spectra obtained and the corresponding spectra
of related isostructural conductors based on the ET molecule, and also the properties of the crystal structure of the investigated
compounds. An electronic transition between the ET molecules of the dimer (ET)
2
+
in the spectral region 700–5500 cm−1 has been identified, as have the features of the electronic-vibrational structure arising as a consequence of the interaction
of this transition with the completely symmetric intramolecular vibrations of the ET molecule. It is found that the conductor
with the stronger dimer interaction between the ET molecules has the higher the transition temperature.
Fiz. Tverd. Tela (St. Petersburg) 39, 1313–1319 (August 1997) 相似文献
4.
A. V. Bazhenov V. V. Kveder A. A. Maksimov I. I. Tartakovskii R. A. Oganyan Yu. A. Ossipyan A. I. Shalynin 《Journal of Experimental and Theoretical Physics》1998,86(5):1030-1034
Raman light scattering and IR absorption spectra of samples containing multilayer carbon nanotubes in different stages of
purification by the selective oxidation technique have been investigated. It was found that the Raman spectra of carbon nanotubes
exhibit softening of the mode at 1582 cm−1 corresponding to E
2g
vibrations of graphite hexagons and a line at 120 cm−1 due to the radial vibrations of nanotubes. In IR absorption spectra measured in the region of 0.07–0.3 eV, several sets of
lines with a spacing of 15 meV (120 cm−1) between lines of each group have been detected. We suggest that each group corresponds to electron transitions generating
electron-hole pairs in semiconducting nanotubes and contains a phononless 00-line and its phonon replicas with spacing between
them equal to the “breathing” mode energy of 120 cm−1. Measurements of electric conductivity at a frequency of 9300 MHz indicate that, in addition to semiconducting nanotubes,
the samples contain nanotubes with properties of a highly disordered semimetal.
Zh. éksp. Teor. Fiz. 113, 1883–1891 (May 1998) 相似文献
5.
The Raman spectrum of polycrystalline α-naphthylamine was recorded in the region 100–4000 cm−1. Polarisation measurements were made in CS2 and CHCl3 solutions. The infrared spectrum was recorded in nujol mull in the region 200–4000 cm−1. The resolution was better than 2 cm−1 and the accuracy of the measurements was within ± 2 cm−1 for all the spectra. Vibrational assignments have been proposed for the observed frequencies. Out of the 54 normal modes
of vibrations, 51 modes could be observed experimentally. 相似文献
6.
N. A. Borisevich D. K. Buslov V. A. Khripach V. N. Zhabinsky 《Journal of Applied Spectroscopy》2008,75(5):637-643
Comparative analysis of IR spectra of S-and R-isomers differing in the configuration of OH groups in the side chain of biologically
active 24-epi-and 28-homocastasterones and 24-epi-and 28-homobrassinolides is carried out. Stretching vibration frequencies
of H-bonded OH groups of isomers of corresponding brassinosteroids practically coincide. The optical density in maxima of
these bands is higher in spectra of the R-isomers. Alteration in the configuration of the OH groups weakly influences also
the band intensities of CH3, CH2, and CH groups. Band intensities of stretching vibrations of associated C=O groups of S-and R-isomers also neglibibly differ
from each other. Their frequency characteristics do not experience substantial changes. These features differ considerably
in IR spectra of castasterones and brassinolides. For castasterones, the difference in frequencies of band maxima of free
and bound C=O groups amounts to ∼15 cm−1; for brassinolides, 23 cm−1. Intensities of both bands are approximately equal in spectra of castasterones. The band intensity of free C=O groups of
brassinolides is considerably lower than that of H-bonded ones. The above spectral differences can be used to identify these
brassinosteroids. Frequencies of both symmetric and antisymmetric deformation vibrations of CH3 and CH2 groups are close in spectra of all brassinosteroids studied. The frequency of CH2 in a CH2-OC group belongs only to brassinolides; of deformation vibrations of CH in a CH-C=O group, to castasterones. The frequency
of stretching vibrations of C-O-C and C-O groups is observed only in spectra of brassinolides. In the region 1130–900 cm−1 of IR spectra of brassinosteroids, stretching vibrations of CC, CCH, and C-OH groups are predominantly observed. In the frequency
range 1130–995 cm−1, the optical density of band maxima of S-isomers is higher than that of R-isomers, which can be used to identify isomers.
At the same time frequencies of corresponding bands of isomers practically coincide. Differences in the structure of the side
chain of brassinosteroids do not influence essentially the frequency characteristics of the IR spectra. The exception is the
band related to stretching vibrations ν(C23-OH) of the side chain which features a considerable frequency νmax ≈ 983 cm−1 only in spectra of R-isomers of homocastasterone and brassinolide.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 5, pp. 623–630, September–October, 2008. 相似文献
7.
We report on the vibrational properties of spinel LiMn2O4 and its electrochemically delithiated forms LixMn2O4. Raman scattering and infrared absorption spectra have been studied as a function of the delithiation content in the wavenumber
range 50–700 cm−1. Results show that lithium ions can be extracted at room temperature to obtain Lix[Mn2]O4 (0.3≤x≤1.0) without disrupting the [Mn2]O4 array. The normal modes of the spinel LiMn2O4 have been discussed in the O
h
7
symmetry and vibrations due to lithium ions with their oxygen neighbors have been identified at ca. 400 cm−1.
Paper presented at the 3rd Euroconference on Solid State Ionics, Teulada, Sardinia, Italy, Sept. 15–22, 1996 相似文献
8.
We report the vibrational properties of lithium-intercalated SnSySe2−y (0≤y≤2) layered compounds. Infrared absorption spectra have been recorded as a function of temperature in the frequency range
50–600 cm−1. The new bands are interpreted as vibrational modes of lithium atoms against the nearest-neighbouring-chalcogen atoms located
in the van der Waals gap. Results are analyzed in terms of stretching vibrations of Li-S4 and Li-S6 entities. From a comparison of the spectra, it is concluded that lithium ions are more likely to occupy tetrahedral sites
in the lithium-rich phases. Using a simple model of lattice dynamics, the coupling force constants are determined and compared
with those of the pristine materials.
Paper presented at the 2nd Euroconference on Solid State Ionics, Funchal, Madeira, Portugal, Sept. 10–16, 1995 相似文献
9.
S. F. Shkirman L. L. Gladkov V. K. Konstantinova K. N. Solov’ev 《Journal of Applied Spectroscopy》1999,66(3):400-409
Quasi-line fluorescence and fluorescence-excitation spectra of tetrabenzoporphin (H2TBP) and its deuterated derivative (D2TBP) in n-octane at 77 K were measured and analyzed. A calculation of normal vibrations of the H2TBP and D2TBP molecules has been performed. The normal vibrations of these molecules were calculated with the use of the valence force
fields of porphin and phenanthrene (the direct spectral problem was solved). Good agreement between the calculated and measured
frequencies of the investigated normal vibrations has been obtained without correction of the transfered force constants.
A detailed interpretation of the fluorescence spectra obtained is presented. It is shown that on deuteration of H2TBP, the behavior of the quasi-lines in the fluorescence-excitation spectra in the region of resonance with the S2←S0 transition becomes more complex.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 66, No. 3, pp. 375–382, May–June, 1999. 相似文献
10.
A. N. Murashkevich A. S. Lavitskaya T. I. Barannikova I. M. Zharskii 《Journal of Applied Spectroscopy》2008,75(5):730-734
The composites xTiO2-(1−x)SiO2 (x = 0.1, 0.5, 0.9) were obtained by coprecipitation from solutions of alkoxides: tetraethoxysilane (TEOS) and titanium tetraisopropoxide
(TIPT). Intermolecular interaction of the components of the composite is apparent in the IR absorption spectra in the 928–952
cm−1 region, and is connected with bending vibrations of the Si-O-Ti bond.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 5, pp. 724–728, September–October, 2008. 相似文献
11.
12.
V. V. Kveder V. D. Negrii É. A. Shteinman A. N. Izotov Yu. A. Osip’yan R. K. Nikolaev 《Journal of Experimental and Theoretical Physics》1998,86(2):405-411
Photoluminescence, optical absorption spectra, and photoluminescence excitation spectra were measured on large (2–3 mm), very
pure crystals of fullerene C60 at 5 K. It is shown that the main contribution to the photoluminescence of these crystals is from singlet and triplet excitons
captured on crystal defects. The concentration of these defects does not exceed 1018 cm−23, and the lifetime of triplet excitons on these defects is about 3 ms. It is shown that the symmetry distortion of the C60 molecules at the defects is rather large and causes the oscillator strength of the zero-phonon optical transitions to be
comparable to the most intense optical transitions with the participation of intramolecular vibrations.
Zh. éksp. Teor. Fiz. 113, 734–746 (February 1998) 相似文献
13.
We have recorded the fluorescence excitation spectra of three heterocyclic compounds with a chain structure [BPO (2-phenyl-5-(4-diphenylyl)oxazole),
POPOP (1,4-di[2-(5-phenyloxazolyl)]benzene, and TOPOT (1,4-di[2-(5-n-tolyloxazolyl)]benzene] and the fluorescence spectra
of POPOP, under conditions where the molecules were cooled in an ultrasonic helium jet. A line structure is observed in the
spectra of POPOP and TOPOT; for the BPO molecules, whose configuration changes considerably during electronic excitation,
vibrational structure is apparent only in the low-frequency region of the excitation spectrum, and a diffuse spectrum is recorded
starting from ν
0
0
+ 200 cm−1. For all the compounds, in the spectra we recorded vibrations with frequencies up to 100 cm−1, arising due to the flexibility of the molecular structure. The rotational contours of the lines for the electronic and vibronic
transitions of the POPOP molecules (Trot = 10.5 K) and TOPOT molecules (Trot = 15 K) are structureless and bell-shaped. The degree of polarization of the fluorescence Pfl for the jet-cooled POPOP molecules for excitation of vibrations along the absorption band up to 2000 cm−1 above ν
0
0
is practically constant (∼8.4%) and matches Pfl for high-temperature vapors.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 6, pp. 728–734, November–December, 2006. 相似文献
14.
V. I. Solomonov A. V. Spirina E. G. Vovkotrub V. N. Strekalovskii 《Optics and Spectroscopy》2011,110(6):890-896
Pulsed cathodoluminescence spectra of Nd3+:Y2O3 compacts registered after their annealing in air at a temperature above 950°C exhibit a structured band in the range 610–660
nm with four well-resolved components located at wavelengths of 620.6, 630.6, 645.3, and 655.6 nm. At the same time, the lattice
parameter of the cubic yttria increases, and the color of samples changes from light blue to yellowish. In addition, the nearly
complete absorption of the intrinsic luminescence band of yttria is observed in the range of 380–600 nm with a center at λ
= 485 nm. We assume that these effects are caused by oxygen molecular ions O2−, which are formed in cubic yttria due to the penetration of oxygen into natural anion vacancies. The frequencies of vibrations
of the ground and excited states of the oxygen molecular ion has been determined. 相似文献
15.
A. M. Efimov A. I. Ignat’ev N. V. Nikonorov E. S. Postnikov 《Optics and Spectroscopy》2011,111(3):426-433
We have measured the UV absorption spectra of photothermorefractive glasses of the system Na2O-ZnO-Al2O3-NaF-SiO2 doped by cerium oxide in the range of (2.8–5.0) × 104 cm−1 (360–200 nm). The spectra have been processed by the method of dispersion analysis based on the analytical convolution model
for the complex dielectric function of glasses. We show that the absorption band centered at 3.3 × 104 cm−1 (∼303 nm) that is attributed to the transition 2F
5/2 → 5d in the Ce3+ ion, is an envelope of three spectral components. The broad absorption range (3.5–4.7) × 104 cm−1 (200–270 nm) that is commonly interpreted as a charge transfer band of the Ce(IV) valence state, is an envelope of at least
three spectral components. 相似文献
16.
The fluorescence spectra of CS2 and SO2 have been studied at three incident photon wavelengths of 121.6, 73.6–74.4 and 58.4 nm and relative production cross sections
for different product states have been measured. The CS(A
1Π→X
1Σ+) system between 240 and 290nm has been obtained when CS2 is photoexcited at 121.6nm whereas CS
2
+
(B
2Σ
u
+
→X
2Π
g
) and CS
2
+
(A
2Π
u
→X
2Π
g
) systems have been produced between 276 and 295 and 437 and 555nm respectively when excited by both the incident photon wavelengths
of 73.6–74.4 and 58.4nm. The fluorescence spectra of SO2 obtained at 121.6 and 73.6–74.4nm include the vibrational bands of SO(A
3Π→X
3Σ−) and SO(B
2Π−→X
3Σ−) systems from 240 to 268 and 268 to 442nm respectively whereas the emission spectrum at 58.4nm, has contributions from the
two SO systems and SO+(A
2Π→X
2Π) system. In all these emission spectra, the fluorescence bands of different systems have been analyzed and their relative
production cross sections have been measured. The results obtained in the present investigations have been compared with a
few recent reliable measurements reported in literature. 相似文献
17.
D. S. Umreiko A. P. Zazhogin A. I. Komyak S. D. Umreiko 《Journal of Applied Spectroscopy》2007,74(4):479-484
We have examined general rules for the change of frequency of stretching vibrations of UO
2
2+
(uranyl) as a function of U-O and uranium-ligand interatomic distances. We analyzed the behavior of these frequencies as
a function of donor number (DN) of the organic ligand by studying IR absorption and visible luminescence spectra. A linear
correlation was found. We proposed spectroscopic methods for determining the DN of ligands, which are difficult to estimate
by other methods, and the composition and structure of uranium complexes.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 74, No. 4, pp. 433–438, July–August, 2007. 相似文献
18.
R. M. Vlasova O. O. Drozdova V. N. Semkin R. N. Lyubovskaya 《Physics of the Solid State》1998,40(9):1447-1450
We present here for the first time polarized reflection spectra and optical conductivity spectra of single crystals of the
newly deuterated organic conductor k-(D8-BEDT-TTF)2[Hg(SCN)2Br] at room temperature. The spectral region investigated is 700–40 000 cm−1. We examined the effect of deuteration on electronic and electron-vibrational transitions observed in the spectra. The observed
shift of the electron “dimer” transition in the infrared toward lower frequencies upon deuteration is linked with an increase
in the interaction between neighboring, mutually perpendicular dimers in the structure of the deuterated crystal. A lowering
of the symmetry of the BEDT-TTF molecule is demonstrated in crystals similar to k-(BEDT-TTF)2[Hg(SCN)2Br], relative to the symmetry D
2h
of the free molecule. We refine the assignment of the spectral features determined by the interaction of electrons with the
fully-symmetric intramolecular vibrations of the C=C, C-S, and C-C-H bonds of the BEDT-TTF molecule.
Fiz. Tverd. Tela (St. Petersburg) 40, 1595–1598 (September 1998) 相似文献
19.
Spectroscopic properties of praseodymium ions-doped erbium oxalate (Er2(C2O4)3 · nH2O) crystals have been investigated. The crystals were grown by hydro silica gel method under suitable pH conditions and by
single diffusion method. The well-grown crystals are bright and transparent. The dark green colour of these crystals changes
with the variation of the concentrations of the dopant ions. The absorption spectra have been measured in the region 200–800
nm at room temperature. Judd–Ofelt intensity parameters for f–f transitions of the Pr3+ ions have been determined as Ω2 = 166.7, Ω4 = 1.103 and Ω6 = 2.898. Analyses of the absorption spectra also show a possible energy transfer from the host material to the dopant. 相似文献
20.
R. M. Vlasova N. V. Drichko B. V. Petrov V. N. Semkin E. I. Zhilyaeva R. N. Lyubovskaya I. Olejniczak A. Kobayashi H. Kobayashi 《Physics of the Solid State》2004,46(11):1985-1993
Polarized reflectance and optical conductivity spectra of single crystals of two new isostructural organic conductors based
on the BEDT-TSeF molecule, namely, the κ-(BETS)4Hg2.84Br8 superconductor (T
c
=2 K) and the κ-(BETS)4Hg3Cl8 metal, which undergoes a smooth transition to the dielectric state near 35 K, have been obtained in the spectral region 700–6500
cm−1 at temperatures of 300–15 K. At 300 K, the spectra of both compounds are nearly identical and differ from the Drude spectrum
characteristic of metals. The nature of the observed difference is discussed, and the spectra are described in terms of a
cluster approach with inclusion of electron-electron correlations in the Hubbard approximation combined with the Drude model.
The parameters of the theory were determined, including the electron transfer integrals between molecules in a cluster. The
spectra in the conducting plane of the crystals were found to be essentially anisotropic, which should be assigned to specific
features of in-plane interaction between molecules. The spectra of the superconductor and the metal become increasingly different
as the temperature is lowered. The spectra of the metal obtained for T<150 K exhibit splitting of the broad electronic maximum in the mid-IR region into two bands, which is accompanied by a splitting
of a vibronic feature deriving from electron interaction with intramolecular BETS vibrations of ν3(A
g
) symmetry. No such splitting is observed in the superconductor spectra with decreasing temperature.
__________
Translated from Fizika Tverdogo Tela, Vol. 46, No. 11, 2004, pp. 1921–1929.
Original Russian Text Copyright ? 2004 by Vlasova, Drichko, Petrov, Semkin, Zhilyaeva, Lyubovskaya, Olejniczak, A. Kobayashi,
H. Kobayashi. 相似文献