scholarly journals Spectral shifts of BODIPY derivatives: a simple continuous model

2019 ◽  
Vol 18 (6) ◽  
pp. 1315-1323 ◽  
Author(s):  
Mette L. H. Sørensen ◽  
Tom Vosch ◽  
Bo W. Laursen ◽  
Thorsten Hansen
Keyword(s):  
Absorption Spectra ◽  
Continuous Model ◽  
Spectral Shifts ◽  
Linear Molecules

The photophysics of substituted BODIPY dyes, as well as the corresponding linear molecules, is captured by a simple Hückel model. The observed trend in the absorption spectra of chalcogen-substituted dyes can be rationalized in terms of the electronegativity of substituents.

Spectral Shifts in the Absorption Spectra of EDA Complexes in Solution

1966 ◽  
Vol 44 (12) ◽  
pp. 4642-4643 ◽  
Author(s):  
H. W. Offen ◽  
M. S. F. A. Abidi
Keyword(s):  
Absorption Spectra ◽  
Spectral Shifts

Lichtabsorption von Farbstoff-Molekülpaaren in Sandwichsystemen aus monomolekularen Schichten

1969 ◽  
Vol 24 (11) ◽  
pp. 1821-1830 ◽  
Author(s):  
V. Czikkely ◽  
G. Dreizler ◽  
H. Försterling ◽  
H. Kuhn ◽  
J. Sondermann ◽  
...  
Keyword(s):  
Absorption Spectra ◽  
Electron Gas ◽  
Quantitative Agreement ◽  
Wave Functions ◽  
Perturbation Approach ◽  
Coating Process ◽  
Electronic Interaction ◽  
Dye Molecules ◽  
Spectral Shifts ◽  
Intensity Changes

Abstract The absorption spectra of cyanine-like dye molecules in monolayer assemblies are investigated. Pairs between two different dye molecules were obtained by superposing monolayers containing the first and second dye respectively. The spectra of these aggregates are compared with the spectra of the corresponding monomers. The spectral shifts are calculated theoretically using a perturbation approach based on the timedependent Schrödinger equation. The electronic interaction integrals are calculated from wave functions given by the onedimensional electron gas theory making allowance for the polarization of the π-electrons and the solvent. A quantitative agreement between predicted and observed shifts and intensity changes is found. It is concluded from our experiments that during the coating process of the second dye layer the dye molecules in this layer are able to diffuse within the layer to form pairs with the dye molecules fixed in the first layer.

scholarly journals SPECTRAL SHIFTS OF SEMICONDUCTOR CLUSTERS

1996 ◽  
Vol 03 (01) ◽  
pp. 121-125 ◽  
Author(s):  
ANTONIETTA TOMASULO ◽  
MUSHTI V. RAMAKRISHNA
Keyword(s):  
Experimental Data ◽  
Absorption Spectra ◽  
Coulomb Interaction ◽  
Electronic Absorption ◽  
Cluster Size ◽  
Electronic Absorption Spectra ◽  
Spectral Shifts ◽  
Semiconductor Clusters ◽  
Small Clusters

The shifts of the electronic absorption spectra of GaAs and GaP semiconductor clusters are calculated using accurate pseudopotentials. In the absence of experimental data at present, these calculations provide estimates for the expected spectral shifts in these clusters. In addition, these calculations show that Coulomb interaction between the electron and hole dominates over the confinement energy in small clusters, with the result that the electronic absorption spectra of small clusters exhibit redshift instead of blueshift as the cluster size is decreased.

scholarly journals Dipole Moments and Polarizabilities of Benzophenones Estimated from Spectroscopic Measurements

1981 ◽  
Vol 36 (8) ◽  
pp. 909-912
Author(s):  
M. Stori
Keyword(s):  
Absorption Spectra ◽  
Dipole Moments ◽  
Cavity Radius ◽  
Spectroscopic Measurements ◽  
Spectral Shifts

Abstract The effect of microenvironment on the absorption spectra of benzophenone and its aminoderivatives in n-heptane/n-butanol and n-heptane/benzene mixtures was investigated. The local dielectic constants, the composition of the solvatation shell, the Onsager cavity radius "a" and the values of a/a3 (α - the polarizability of solute molecules) have been evaluated from the spectral shifts.

scholarly journals Effects of substituents on the electronic absorption spectra of 3-n-(4-substituted phenyl)-5-carboxy uracils in different solvents. Part II.

2000 ◽  
Vol 65 (2) ◽  
pp. 81-86 ◽  
Author(s):  
N. Valentic ◽  
G. Uscumlic ◽  
M. Radojkovic-Velickovic
Keyword(s):  
Absorption Spectra ◽  
Electronic Absorption Spectra ◽  
Reaction Medium ◽  
Electron Pairs ◽  
Linear Free Energy ◽  
Spectral Shifts ◽  
Resonance Interactions ◽  
Energy Relationships ◽  
Uv Visible ◽  
Substituted Uracils

Absorption spectra of some 3-N-(4-substituted phenyl)-5-carboxy uracils, previously determined in twelve solvents, are correlated with substituent sp + values or by dual substituent parameter correlations involving sI and sR + values. The substituents at the phenyl nucleus are as follows: H, Cl, Br, I, Me, Et, OMe, COOH and NO2. Considering the structure of the investigated system, it is very probable that the effect of the substituent at the phenyl nucleus on the electronic spectra of the substituted uracils is influenced by resonance interactions between the electron pairs of both the nitrogen atoms, the carbonyl groups and the substituent itself. The polarity of the reaction medium also affects the complex resonance interactions in the molecules of the investigated compounds. The obtained results support a suggestion made by Brownlee and Topsom that UV/visible spectral shifts can conform to reasonable precise linear free energy relationships if the substituent is not a part of the chromophoric system.

Ultraviolet Absorption of Refractory Elements by a Dual Laser Plasma Method

1988 ◽  
Vol 102 ◽  
pp. 243-246
Author(s):  
J.T. Costello ◽  
W.G. Lynam ◽  
P.K. Carroll
Keyword(s):  
Absorption Spectra ◽  
Laser Plasma ◽  
Optical Pulse ◽  
Ionic Species ◽  
Neutral Species ◽  
Plasma Method ◽  
Plasma Technique ◽  
Refractory Elements ◽  
Delay Times ◽  
Dual Laser

AbstractThe dual laser-produced plasma technique for the study of ionic absorption spectra has been developed by the use of two Q-switched ruby lasers to enable independent generation of the absorbing and back-lighting plasmas. Optical pulse handling is used in the coupling cicuits to enable reproducible pulse delays from 250 nsec. to 10 msec, to be achieved. At delay times > 700 nsec. spectra of essentially pure neutral species are observed. The technique is valuable, not only for obtaining the neutral spectra of highly refractory and/or corrosive materials but also for studying behaviour of ionic species as a function of time. Typical spectra are shown in Fig. 1.

XUV Absorption Spectra of Carbon Ions

1988 ◽  
Vol 102 ◽  
pp. 71-73
Author(s):  
E. Jannitti ◽  
P. Nicolosi ◽  
G. Tondello
Keyword(s):  
Absorption Spectra ◽  
Cross Section ◽  
Theoretical Calculations ◽  
Photoionization Cross Section ◽  
Carbon Ions

AbstractThe photoabsorption spectra of the carbon ions have been obtained by using two laser-produced plasmas. The photoionization cross-section of the CV has been absolutely measured and the value at threshold, σ=(4.7±0.5) × 10−19cm2, as well as its behaviour at higher energies agrees quite well with the theoretical calculations.

Electron microscopic assays of restriction endonuclease cutting, exonuclease digestion, and hybridization

1984 ◽  
Vol 42 ◽  
pp. 686-687
Author(s):  
Mark Hannibal ◽  
Jacob Varkey ◽  
Michael Beer
Keyword(s):  
Electron Microscope ◽  
Low Temperature ◽  
Restriction Endonuclease ◽  
Double Helix ◽  
Test Material ◽  
Electron Microscopic ◽  
Exonuclease Iii ◽  
Dna Molecule ◽  
Linear Molecules ◽  
Exonuclease Digestion

Workman and Langmore have recently proposed a procedure for isolating particular chromatin fragments. The method requires restriction endonuclease cutting of the chromatin and a probe, their digestion with two exonucleases which leave complimentary single strand termini and low temperature hybridization of these. We here report simple electron microscopic monitoring of the four reactions involved.Our test material was ϕX-174 RF DNA which is cut once by restriction endonuclease Xho I. The conversion of circles to linear molecules was followed in Kleinschmidt spreads. Plate I shows a circular and a linear DNA molecule. The rate of cutting is shown in Figure 1.After completion of the endonuclease cutting, one portion of the DNA was treated with exonuclease III, an enzyme known to digest the 3' terminals of double helical DNA. Aliquots when examined in the electron microscope reveal a decreasing length of double helix and increasing bushes at the ends.

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