Electronic Transitions in a Classical Antiferroelectric Banana-Shaped Compound

2010 ◽  
Vol 428-429 ◽  
pp. 317-321
Author(s):  
Bao Gai Zhai ◽  
Yuan Ming Huang
Keyword(s):  
Liquid Crystal ◽  
Optical Absorption ◽  
Absorption Spectra ◽  
Ethyl Alcohol ◽  
Electronic Structures ◽  
Tight Binding ◽  
Methyl Benzoate ◽  
Electronic Transitions ◽  
Optical Absorption Spectra ◽  
Dilute Solutions

The electronic transitions in a classical banana-shaped liquid crystal 1,3-phenylene-bis [4-(4-octylphenylimino) methyl] benzoate have been investigated by measuring its optical absorption spectra in dilute solutions of ethyl alcohol and by calculating its electronic structures with extended Hückel tight binding program. The banana-shaped compound shows strong absorptions at 240, 280, 350 nm, respectively. On the basis of the calculated electronic structures, the three strong absorptions can be assigned to the *, n*, and nn* electronic transitions in this banana-shaped compound.

Optical absorption spectra of octahedrally bonded Fe3+ in vesuvianite

1968 ◽  
Vol 5 (1) ◽  
pp. 89-92 ◽  
Author(s):  
P. G. Manning
Keyword(s):  
Optical Absorption ◽  
Energy Range ◽  
Absorption Spectra ◽  
Excited States ◽  
Ground State ◽  
Electronic Transitions ◽  
Optical Absorption Spectra ◽  
Sharp Band ◽  
Individual Bands ◽  
The Individual

The optical absorption spectra of green vesuvianite crystals from Lowell County, Vermont, are reported in the energy range 12 000 cm−1 to 30 000 cm−1. The principal absorptions have been attributed to octahedrally bonded Fe3+ and the individual bands have been assigned to spin-forbidden electronic transitions from the 6A1 ground state to excited states in Fe3+. In particular, the 6A1 → 4A14E(G) transition is marked by a relatively sharp band at 21 600 cm−1.

Magneto-optical properties of ABC-stacked trilayer graphene

2015 ◽  
Vol 17 (24) ◽  
pp. 15921-15927 ◽  
Author(s):  
Yi-Ping Lin ◽  
Chiun-Yan Lin ◽  
Yen-Hung Ho ◽  
Thi-Nga Do ◽  
Ming-Fa Lin
Keyword(s):  
Optical Properties ◽  
Optical Absorption ◽  
Absorption Spectra ◽  
Tight Binding ◽  
Tight Binding Model ◽  
Optical Absorption Spectra ◽  
Binding Model ◽  
Trilayer Graphene

The generalized tight-binding model is developed to investigate the magneto-optical absorption spectra of ABC-stacked trilayer graphene.

Electronic structures and optical properties of arsenene and antimonene under strain and an electric field

2018 ◽  
Vol 6 (1) ◽  
pp. 83-90 ◽  
Author(s):  
Huabing Shu ◽  
Yunhai Li ◽  
Xianghong Niu ◽  
JiYuan Guo
Keyword(s):  
Optical Properties ◽  
Optical Absorption ◽  
Electric Field ◽  
Absorption Spectra ◽  
Electronic Structures ◽  
Optical Absorption Spectra

The optical absorption spectra of hexagonal arsenene (β-As) and antimonene (β-Sb).

Optical Absorption Study of Hydrogen In Zn-Doped Si

1998 ◽  
Vol 513 ◽  
Author(s):  
M. Suezawa
Keyword(s):  
Optical Absorption ◽  
Absorption Spectra ◽  
Hydrogen Atmosphere ◽  
Electronic Transitions ◽  
Optical Absorption Spectra ◽  
Hydrogen Atoms ◽  
Ir Spectrometry ◽  
Co Doping ◽  
Ft Ir ◽  
Hydrogen Bound

ABSTRACTWe studied the interaction between hydrogen (H) and Zn or Zn-related defects in Zn-doped Si crystals from the measurements of optical absorption spectra of hydrogen bound to Zn or Znrelated defects. We doped Si crystals with Zn by annealing the crystals in Zn vapor at 1200°C followed by quenching. After Zn-doping, we doped specimens with H by annealing them in a hydrogen atmosphere followed by quenching. We measured optical absorption spectra of the above specimens at about 6 K by means of FT-IR spectrometry. Many optical absorption peaks were observed; some are due to electronic transitions and some are due to vibrational transitions of H vibration. Hydrogen atoms are known to passivate Zn acceptors since the optical absorption intensity associated with electronic transitions become much weaker after hydrogenation. Absorption peaks associated with H vibration are known to be related to complexes composed of one Zn atom and two hydrogen atoms. We concluded this from studies on the effect of co-doping with H and deuterium and the effect of Zn isotopes on the optical absorption spectra due to H.

Origin of the Photoluminescence of a Banana-Shaped Liquid Crystal

2010 ◽  
Vol 663-665 ◽  
pp. 146-149 ◽  
Author(s):  
Yuan Ming Huang ◽  
Bao Gai Zhai ◽  
Qing Lan Ma
Keyword(s):  
Schiff Base ◽  
Liquid Crystal ◽  
Optical Absorption ◽  
Benzene Ring ◽  
Electronic Structures ◽  
Dilute Solutions ◽  
Long Tail ◽  
Benzene Rings ◽  
Pl Spectrum

We have investigated the optical absorption and photoluminescence (PL) of a classical banana-shaped liquid crystal, 1,3-phenylene-bis[4-(4'-nonyloxy)phenyliminomethyl]benzoate, in dilute solutions of tetrahydrofuran. Upon the 325 nm excitation from a helium-cadmium laser, the dilute tetrahydrofuran solutions of the banana-shaped compound gives off strong PL with its peak located at about 380 nm (3.26 eV). Interestingly the PL spectrum of the banana-shaped compound has a long tail that extends beyond 500 nm. In order to explore the origin of the PL, we have calculated the electronic structures of the three chromophores in the banana-shaped compound: the central benzene ring (chromophore A), the carbonyl linkage (chromophore B), and the Schiff base bridged two benzene rings in the branched arms of the molecule (chromophore C). Our results have shown that chromophore C is responsible for the 380 nm PL band where the chromophore B is responsible for the long tail in the recorded PL.

Control of the Luminescence Properties in Polythiophenes Solutions by Interring Rotational Disorder

1997 ◽  
Vol 488 ◽  
Author(s):  
S. Luzzati ◽  
G. Bongiovanni ◽  
M. Catellani ◽  
M. A. Loi ◽  
A. Milani ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Optical Absorption ◽  
Absorption Spectra ◽  
Luminescence Spectra ◽  
Visible Range ◽  
Optical Absorption Spectra ◽  
Photoluminescence Properties ◽  
Dilute Solutions ◽  
Thiophene Based Polymers

AbstractThe photoluminescence properties of thiophene-based polymers obtained by the random copolymerization of 3,4-dibutylthiophene and 3-butylthiophene are reported. Optical absorption spectra, cw photolumninescence (PL) spectra, PL quantum efficiencies and PL decays have been measured in dilute solutions. By varying the copolymer chemical composition it is possible to tune the intensity and the color of the luminescence spectra in the whole visible range. We evidence the role of disorder, controlled by interring rotations, as the tuning factor for the disexcitation pathway of the photoexcitations in these materials.

Modulating the electronic structures and optical absorption spectra of BeO nanotubes by uniaxial strain

2010 ◽  
Vol 97 (5) ◽  
pp. 051901 ◽  
Author(s):  
Jiangang He ◽  
Kechen Wu ◽  
Rongjian Sa ◽  
Qiaohong Li ◽  
Yongqin Wei
Keyword(s):  
Optical Absorption ◽  
Absorption Spectra ◽  
Electronic Structures ◽  
Uniaxial Strain ◽  
Optical Absorption Spectra

THE OPTICAL ABSORPTION SPECTRA OF SOME ANDRADITES AND THE IDENTIFICATION OF THE 6A1→4A14E(G) TRANSITION IN OCTAHEDRALLY BONDED Fe3+

1967 ◽  
Vol 4 (6) ◽  
pp. 1039-1047 ◽  
Author(s):  
P. G. Manning
Keyword(s):  
Optical Absorption ◽  
Absorption Spectra ◽  
Electronic Transitions ◽  
Optical Absorption Spectra ◽  
Independent State ◽  
Field Independent ◽  
Impurity Ions

The optical absorption spectra of andradites from three different localities are reported. The spectra show a very sharp d–d band at 22 700 cm−1 (440 mμ) that has been assigned to electronic transitions to the first field-independent state (4A14E(G)) in octahedrally bonded Fe3+. A strong broad d–d absorption at 19 000 cm−1 in the high-Ti andradite (melanite) has been assigned to octahedrally bonded Ti3+. The andradites also show broad bands at 12 500 cm−1, 16 500 cm−1, and 21 400 cm−1 that are part of the Fe3+ spectrum.The andradite spectra have been compared to the spectrum of an almandine-pyrope. The conclusion is reached that the Fe3+ octahedra in andradite and the pyralspite garnets are different. There is no justification, therefore, in giving an almandine-pyrope (that contains Fe3+) an andradite content on the basis of Fe3+ analyses. The Fe3+ atoms in pyralspites are better regarded as impurity ions.

Sign in / Sign up

Export Citation Format

Share Document