VIBRATIONAL ISOTOPE SHIFTS OF ABSORPTION BANDS OF N2 IN THE SPECTRAL REGION 720–830 Å

1964 ◽  
Vol 42 (6) ◽  
pp. 1087-1096 ◽  
Author(s):  
Masaru Ogawa
Keyword(s):  
Absorption Spectra ◽  
Spectral Region ◽  
Normal Incidence ◽  
Rydberg Series ◽  
Absorption Bands ◽  
Isotope Shifts ◽  
Previous Assignment ◽  
Vibrational Constants ◽  
Concave Grating

Using a normal-incidence vacuum spectrograph with a 3-meter concave grating, the absorption spectra of 14N2 and 15N2 in the 720–830 Å region have been investigated. From the vibrational isotope shifts, it has been confirmed that the previous assignment given by Ogawa and Tanaka for the Rydberg series converging to the A2Πu state of N2+ was correct. The observed series limits converging to the [Formula: see text] state of 15N2+ are 134735(0,0), 136540(1,0), 138320(2,0), and 140070(3,0) cm−1. The observed vibrational isotope shifts at the series limits in both Rydberg series converging to the A2Πu and the X2Σg+ states of N2+ agree with those values calculated from the known vibrational constants of the A2Πu, and the X2Σg+ states of 14N2+ and the X1Σg+ state of 14N2. In addition to the Rydberg series, four new progressions have been identified tentatively. The observed vibrational quanta of the upper states of these progressions are almost the same, and are, moreover, almost the same as those of the A2Πu state of N2+.

ABSORPTION SPECTRA OF BENZENE AND BENZENE-d6 IN THE VACUUM ULTRAVIOLET

1956 ◽  
Vol 34 (6) ◽  
pp. 596-615 ◽  
Author(s):  
P. G. Wilkinson
Keyword(s):  
Absorption Spectra ◽  
Vacuum Ultraviolet ◽  
Stable Equilibrium ◽  
Normal Incidence ◽  
Rydberg Series ◽  
First Order ◽  
Jahn Teller ◽  
Vibrational Bands ◽  
Vibrational Constants ◽  
Rydberg Transitions

The absorption spectra of benzene and benzene-d6 have been photographed from 1300 Å to 1850 Å in the first order of a 21-ft. normal incidence vacuum spectrograph. The band analysis resulted in the identification of four Rydberg series (over one hundred vibrational bands) in each molecule, converging to ionization potentials of 9.247 ev. (benzene) and 9.251 ev. (benzene-d6). Progressions of the ν2, ν18, and ν20 vibrations are associated with most of the 31 observed Rydberg transitions, and vibrational constants are tabulated for each. The strong intensity and the unusual length of the upper state ν18 (e2g) progression in comparison with the ν2(a1g) progression are interpreted in terms of the Jahn–Teller theorem, and it is concluded that the stable equilibrium nuclear configuration in the Rydberg states is of D2h symmetry.

Excitonic Bands in the Optical Absorption Spectra of A3MX6 and A3M2X9 (A = MeNH3, Me2NH2, Me3NH, Me4N; M = Bi, Sb; X = Cl, Br, I)

1994 ◽  
Vol 49 (6) ◽  
pp. 849-851 ◽  
Author(s):  
G. C. Papavassiliou ◽  
I. B. Koutselas
Keyword(s):  
Optical Absorption ◽  
Absorption Spectra ◽  
Spectral Region ◽  
Visible Spectral Region ◽  
Optical Absorption Spectra ◽  
Absorption Bands ◽  
Uv Visible ◽  
Low Dimensional

The title compounds (natural low-dimensional semiconductors) show strong excitonic optical absorption bands in the UV-visible spectral region, because of the dielectric confinement of excitons. as in the cases of other similar systems based on PbX2-4, SnX2-4. PtI - X - PtIV-X , Cdx,Sy-clusters etc

Thickness-Dependent Optical Effects in Infrared Reflection-Absorption Spectra of a Fairly Thick Polymer Layer

2002 ◽  
Vol 56 (1) ◽  
pp. 24-30 ◽  
Author(s):  
Marta KlanjšEk Gunde ◽  
Zorica Crnjak Orel
Keyword(s):  
Absorption Spectra ◽  
Normal Incidence ◽  
Peak Position ◽  
Mean Value ◽  
Absorption Bands ◽  
Medium Thickness ◽  
Peak Intensity ◽  
Infrared Reflection ◽  
Optical Effects ◽  
The Mean

Thickness-dependent intensities and positions of absorption lines in infrared reflection-absorption spectra of thin films on reflective substrates at near-normal incidence are investigated. Two types of absorption bands in a polymer, the weak and the strong, were examined. Their optical properties were determined by the dielectric response function. The optical path of the beam was described by the coherent sum of all successively reflected beams. The thickness-dependent properties of absorption bands were examined in three typical thickness regions. At small thickness, the peak intensity oscillates around the mean value defined by the simple internal absorptance of the beam crossing the double layer. For medium thickness, the peak position swings around the original frequency and its intensity oscillations move above the simple internal absorptance. In layers within the high-thickness region, optical distortions cause large changes in line shape due to approaching the bulk reflectance. A simple analytical interpretation is possible only within the low-thickness region. The width of these thickness regions depends on the absorptivity of the considered band; for strong bands they are considerably narrower than for weak bands. The theoretically predicted effects compare well with those measured in RAS spectra of variously thick silicon resin layers on aluminium substrates.

The photoabsorption of chlorodifluoroethenes in the vacuum ultraviolet

1985 ◽  
Vol 63 (7) ◽  
pp. 1949-1954 ◽  
Author(s):  
Eckart Rühl ◽  
Hans-Werner Jochims ◽  
Helmut Baumgärtel
Keyword(s):  
Energy Range ◽  
Ionization Potential ◽  
Gas Phase ◽  
Absorption Spectra ◽  
Photon Energy ◽  
Vacuum Ultraviolet ◽  
Rydberg Series ◽  
Absorption Bands ◽  
Broad Absorption ◽  
Cis And Trans

The gas phase absorption spectra of 2-chloro-1,1-difluoroethene, cis- and trans-1-chloro-1,2-difluoroethene have been measured in the photon energy range from 6.5 to 25 eV. The π → π* transition is assigned to bands centered around 7.17 – 7.20 eV for all three isomers. Four Rydberg series are observed in all the spectra, converging to the π ionization potential: two np-type Rydberg series, one ns, and one nd series are assigned. The convergence limits are: 9.84 eV (2-chloro-1,1-difluoroethene), 9.86 eV (trans-1-chloro-1,2-difluoroethene), and 9.85 eV (trans-1-chloro-1,2-difluoroethene). In the case of 2-chloro-1,1-difluoroethene four additional Rydberg series are found converging to the nCl ionization potential. The convergence limit of these series is 12.15 eV.Above 12 eV broad absorption bands dominate the spectra.

First Nano-Infrared Spectroscopy and Imaging Measurements of Single Phospholipid Bilayers

2018 ◽  
Author(s):  
Adrian Cernescu ◽  
Michał Szuwarzyński ◽  
Urszula Kwolek ◽  
Karol Wolski ◽  
Paweł Wydro ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Ir Spectroscopy ◽  
Absorption Band ◽  
Spectral Region ◽  
Near Field ◽  
Phospholipid Bilayers ◽  
Model Systems ◽  
Absorption Bands ◽  
Protein Complement ◽  
20 Nm

<div><div>Scattering-mode Scanning Near-Field Optical Microscopy (sSNOM) allows one to obtain absorption spectra in the mid-IR region for samples as small as 20 nm in size. This configuration has made it possible to measure FTIR spectra of the protein complement of membranes. (Amenabar 2013) We now show that mid-IR sSNOM has the sensitivity required to measure spectra of phospholipids in individual bilayers in the spectral range 800 cm<sup>-1</sup>–1400 cm<sup>-1</sup>. We have observed the main absorption bands of the dipalmitoylphosphatidylcholine headgroups in this spectral region above noise level. We have also mapped the phosphate absorption band at 1070 cm<sup>-1</sup> simultaneously with the AFM topography. We have shown that we could achieve sufficient contrast to discriminate between single and multiple phospholipid bilayers and other structures, such as liposomes. This work opens the way to further research that uses nano-IR spectroscopy to describe the biochemistry of cell membranes and model systems.</div></div><div></div>

Mechanism of anionic coordination dimerization of isoprene

1981 ◽  
Vol 46 (7) ◽  
pp. 1600-1606 ◽  
Author(s):  
Jan Bartoň ◽  
Karel Volka ◽  
Miroslav Kašpar ◽  
Vlastimil Růžička
Keyword(s):  
Gas Chromatography ◽  
Alkali Metal ◽  
Absorption Spectra ◽  
Visible Radiation ◽  
Absorption Bands ◽  
Absorption Spectrophotometry ◽  
Spectrophotometric Data ◽  
Oligomeric Forms

The mechanism of controlled anionic coordination dimerization of isoprene (i.e. 2-methyl-1,3-butadiene) in the system tetrahydrofuran-isoprene-alkali metal-dialkylamine was investigated by using absorption spectrophotometry in the range of visible radiation and gas chromatography. The effect of the alkali metal (Li, Na, K) and dialkylamine (dicyclohexylamine, N-isopropylcyclohexylamine, N-methylisopropylamine) on the absorption spectra was tested. By comparing chromatographic and spectrophotometric data, the absorption bands in the range of visible radiation were identified with the existence of π-complexes between oligomeric forms of isoprene and alkali metal dialkylamide.

scholarly journals Unraveling the electrochemical and spectroscopic properties of neutral and negatively charged perylene tetraethylesters

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Christian Wiebeler ◽  
Joachim Vollbrecht ◽  
Adam Neuba ◽  
Heinz-Siegfried Kitzerow ◽  
Stefan Schumacher
Keyword(s):  
Absorption Spectra ◽  
Density Functional ◽  
Energy Levels ◽  
Spectroscopic Properties ◽  
Absorption Bands ◽  
Functional Theory ◽  
Vertical Excitation ◽  
Hartree Fock ◽  
Tauc Plot ◽  
Electrochemical Approach

AbstractA detailed investigation of the energy levels of perylene-3,4,9,10-tetracarboxylic tetraethylester as a representative compound for the whole family of perylene esters was performed. It was revealed via electrochemical measurements that one oxidation and two reductions take place. The bandgaps determined via the electrochemical approach are in good agreement with the optical bandgap obtained from the absorption spectra via a Tauc plot. In addition, absorption spectra in dependence of the electrochemical potential were the basis for extensive quantum-chemical calculations of the neutral, monoanionic, and dianionic molecules. For this purpose, calculations based on density functional theory were compared with post-Hartree–Fock methods and the CAM-B3LYP functional proved to be the most reliable choice for the calculation of absorption spectra. Furthermore, spectral features found experimentally could be reproduced with vibronic calculations and allowed to understand their origins. In particular, the two lowest energy absorption bands of the anion are not caused by absorption of two distinct electronic states, which might have been expected from vertical excitation calculations, but both states exhibit a strong vibronic progression resulting in contributions to both bands.

scholarly journals THE PIGMENT-PROTEIN COMPOUND IN PHOTOSYNTHETIC BACTERIA

1940 ◽  
Vol 23 (4) ◽  
pp. 483-494 ◽  
Author(s):  
C. S. French
Keyword(s):  
Spectral Region ◽  
Photosynthetic Bacteria ◽  
Water Soluble ◽  
Absorption Curve ◽  
Absorption Bands ◽  
Soluble Cell

Absorption curves have been obtained in the spectral region of 450 to 900 mµ for the water soluble cell juice of four species of photosynthetic bacteria, Spirillum rubrum (strain S1), Rhodovibrio sp. (strain Gaffron), Phaeomonas sp. (strain Delft), and Streptococcus varians (strains C11 and orig.). These curves all show maxima at 790 and 590 mµ due to bacteriochlorophyll, whose highest band, however, occurs at 875, 855, or 840 mµ depending on the species. The bacteria that appear red rather than brown have a band at 550 mµ due to a carotinoid pigment. An absolute absorption curve of bacteriophaeophytin has maxima at 530 and 750 mµ. The extraction of cell juice by supersonic vibration does not change the position of the absorption bands or of the light absorbing capacity of the pigment.

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.

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