Substitution pattern dependent behavior of the singlet excited states in symmetrically fluorinated biphenyls

2021 ◽  
Author(s):  
Svetlana M. Sudarkova ◽  
Viktor E. Khinevich ◽  
Ilya N. Ioffe ◽  
Martin Quick ◽  
Sergey A Kovalenko
Keyword(s):  
Excited States ◽  
Solution Phase ◽  
Substitution Pattern ◽  
Dependent Behavior ◽  
Initial Excitation ◽  
Phase Spectra

We report stationary and ultrafast solution-phase spectra for symmetric biphenyls: pristine biphenyl (bP0), 4,4'-difluorobiphenyl (bP2), 2,3,5,6,2',3',5',6'-octafluorobiphenyl (bP8), and perfluorobiphenyl (bP10). Initial excitation to the S3 state in bP0 and bP2,...

Time-dependent behavior of nitric oxide excited states under the effect of electron impact

2021 ◽  
Vol 28 (2) ◽  
pp. 024503
Author(s):  
Mohammed amin Ferdi ◽  
Abdelaaziz Bouziane ◽  
Mourad Djebli
Keyword(s):  
Nitric Oxide ◽  
Electron Impact ◽  
Excited States ◽  
Time Dependent ◽  
Dependent Behavior

Corrole basicity in the excited states: Insights on structure–property relationships

2020 ◽  
Vol 24 (05n07) ◽  
pp. 765-774
Author(s):  
Mikalai M. Kruk ◽  
Dmitry V. Klenitsky ◽  
Lev L. Gladkov ◽  
Wouter Maes
Keyword(s):  
Excited States ◽  
Conformational Changes ◽  
Pyrrole Ring ◽  
Point Of View ◽  
Free Base ◽  
Structure Property ◽  
Substitution Pattern ◽  
Long Wavelength ◽  
Structure Property Relationships ◽  
Fluorescence Measurements

Steady-state fluorescence measurements and quantum-chemical DFT geometry optimizations are applied to extend the structure–property relationships between the free-base corrole macrocycle conformation and its basicity to the lowest excited S[Formula: see text] and T[Formula: see text] states. Direct basicity estimation in the lowest excited S[Formula: see text] state is demonstrated by means of fluorescence quantum yield measurements. The long wavelength T1 tautomer is found to retain its basicity in the S[Formula: see text] state, whereas the short wavelength T2 tautomer shows a noticeable decrease in basicity in the S[Formula: see text] state, which is related to the in-plane tilting of the pyrrole ring to be protonated. The conformational changes upon going from the ground to the lowest excited T[Formula: see text] state and the influence of the meso-aryl substitution pattern on the overall degree of distortions and tilting of the pyrrole ring to be protonated are also discussed from the point of view of macrocycle basicity.

RELATION BETWEEN QUANTUM AND GEOMETRIC DIMENSIONALITIES IN MOLECULAR NONLINEAR OPTICS: BEYOND THE TWO-LEVEL MODEL FOR ANISOTROPIC SYSTEMS

1996 ◽  
Vol 05 (04) ◽  
pp. 671-693 ◽  
Author(s):  
S. BRASSELET ◽  
J. ZYSS
Keyword(s):  
Excited States ◽  
Second Harmonic ◽  
Three Dimensional ◽  
Wavelength Dependence ◽  
Quantum Model ◽  
Substitution Pattern ◽  
Molecular Systems ◽  
Level Model ◽  
Anisotropic Systems ◽  
Two Level Model

The nonlinear optical susceptibilities of two- or three-dimensional molecular systems exhibit variable anisotropic features depending on their structure and substitution pattern. We show that appropriate geometric (e.g. tensorial) considerations combined with an n-level quantum model (n≥3) are able to account for such nonlinear anisotropy as rigorously defined in an invariant spherical formalism by extension of classical linear anisotropy. We call on two kinds of experiments to investigate these properties: firstly, variation of the incident polarization (VIP) in harmonic light scattering (HLS) experiments is being performed to sort out individual tensorial components of the quadratic hyperpolarizability β tensor; secondly, wavelength dependence studies in coherent second harmonic generation (SHG) from poled thin film media are shown at a preliminary stage to be able to designate those excited states responsible for the nonlinear anisotropy.

scholarly journals FEYNMAN DIAGRAMS FOR DISPERSION INTERACTIONS OUT OF EQUILIBRIUM — TWO-BODY POTENTIALS FOR ATOMS WITH INITIAL EXCITATION

2012 ◽  
Vol 14 ◽  
pp. 347-356 ◽  
Author(s):  
HARALD R. HAAKH ◽  
JÜRGEN SCHIEFELE ◽  
CARSTEN HENKEL
Keyword(s):  
Excited States ◽  
Feynman Diagrams ◽  
Intermolecular Potential ◽  
Coupling Scheme ◽  
Intermolecular Force ◽  
Dispersion Interactions ◽  
Initial Excitation ◽  
Unstable States ◽  
Stationary Perturbation Theory ◽  
Stationary Perturbation

Diagrammatic techniques are well-known in the calculation of dispersion interactions between atoms or molecules. The multipolar coupling scheme combined with Feynman ordered diagrams significantly reduces the number of graphs compared to elementary stationary perturbation theory. We review calculations of van der Waals-Casimir-Polder forces, focusing on two atoms or molecules, one of which is excited. In this case, calculations of the corresponding force are notorious for mathematical issues connected with the spontaneous decay of the excitation. Treating such unstable states in a full non-equilibrium theory provides a physical interpretation of apparent contradictions in previous results and underlines the importance of decay processes for the intermolecular potential. This may have important implications on reactions in biological systems, where excited states may be relatively long-lived and the resonant intermolecular force may result in directed Brownian motion.

scholarly journals Substitution pattern on anthrol carbaldehydes: excited state intramolecular proton transfer (ESIPT) with a lack of phototautomer fluorescence

2017 ◽  
Vol 19 (41) ◽  
pp. 28439-28449 ◽  
Author(s):  
S. Chaiwongwattana ◽  
Đ. Škalamera ◽  
N. Došlić ◽  
C. Bohne ◽  
N. Basarić
Keyword(s):  
Excited State ◽  
Proton Transfer ◽  
Excited States ◽  
Intramolecular Proton Transfer ◽  
Dual Emission ◽  
Substitution Pattern ◽  
Locally Excited

Experiments and computations reveal that 1,2-disubstituted anthrol carbaldehydes are not ESIPT reactive, whereas 2,3-disubstituted anthrols undergo efficient barrierless ultrafast ESIPT, where the typical dual emission from locally excited states and tautomers was not observed.

Vuv Spectra Y to Mo

1988 ◽  
Vol 102 ◽  
pp. 239
Author(s):  
M.S.Z. Chaghtai
Keyword(s):  
Excited States ◽  
Spectral Analyses ◽  
Vuv Spectra

Using R.D. Cowan’s computations (1979) and parametric calculations of Meinders et al (1982), old analyses are thoroughly revised and extended at Aligarh, of Zr III by Khan et al (1981), of Nb IV by Shujauddin et Chaghtai (1985), of Mo V by Tauheed at al (1985). Cabeza et al (1986) confirmed the last one largely.Extensive studies have been reported of the 1–e spectra, Zr IV (Rahimullah et al 1980; Acquista and Reader 1980), Nb V (Shujauddin et al 1982; Kagan et al 1981) and Mo VI (Edlén et al 1985). Some interacting 4p54d2levels of these spectra have been reported from our laboratory, also.Detailed spectral analyses of transitions between excited states have furnished complete energy values for J ≠ 1 levels of these spectra during 1970s and 80s. Shujauddin et al (1982) have worked out Nb VI and Tauheed et al (1984) Mo VII from our lab, while Khan et al (1981) share the work on Zr V with Reader and Acquista (1979).

Transition alpha structure in beta-isomorphous Nb-Hf alloys

1987 ◽  
Vol 45 ◽  
pp. 232-233
Author(s):  
R.W. Carpenter ◽  
Changhai Li ◽  
David J. Smith
Keyword(s):  
Solid Solution ◽  
Solution Phase ◽  
Miscibility Gap ◽  
Large Strains ◽  
Solid Solution Phase ◽  
Two Phase ◽  
Diffuse Intensity ◽  
Metastable Form ◽  
The Matrix ◽  
Equilibrium Morphology

Binary Nb-Hf alloys exhibit a wide bcc solid solution phase field at temperatures above the Hfα→ß transition (2023K) and a two phase bcc+hcp field at lower temperatures. The β solvus exhibits a small slope above about 1500K, suggesting the possible existence of a miscibility gap. An earlier investigation showed that two morphological forms of precipitate occur during the bcc→hcp transformation. The equilibrium morphology is rod-type with axes along <113> bcc. The crystallographic habit of the rod precipitate follows the Burgers relations: {110}||{0001}, <112> || <1010>. The earlier metastable form, transition α, occurs as thin discs with {100} habit. The {100} discs induce large strains in the matrix. Selected area diffraction examination of regions ∼2 microns in diameter containing many disc precipitates showed that, a diffuse intensity distribution whose symmetry resembled the distribution of equilibrium α Bragg spots was associated with the disc precipitate.

Excited states of nuclei in -coupling

Physica ◽  
1952 ◽  
Vol 18 (2) ◽  
pp. 1101-1104
Author(s):  
B FLOWERS
Keyword(s):  
Excited States
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