Photosensitivity, substituent and solvent-induced shifts in UV-visible absorption bands of naphthyl-ester liquid crystals: a comparative theoretical approach

2014 ◽  
Vol 41 (6) ◽  
pp. 872-882 ◽  
Author(s):  
P. Lakshmi Praveen ◽  
Durga P. Ojha
Keyword(s):  
Liquid Crystals ◽  
Theoretical Approach ◽  
Absorption Bands ◽  
Visible Absorption ◽  
Uv Visible

Meso-aryl-ß-pyrrolic positions interactions in meso-tetraarylporphyrins: Flat arylporphyrins and building blocks for oligoporphyrins

2004 ◽  
Vol 08 (02) ◽  
pp. 111-119 ◽  
Author(s):  
Henry J. Callot ◽  
Romain Ruppert ◽  
Christophe Jeandon ◽  
Sébastien Richeter
Keyword(s):  
Building Blocks ◽  
Absorption Bands ◽  
Visible Absorption ◽  
Aryl Ring ◽  
Porphyrin Macrocycle ◽  
Uv Visible

Aryl groups bound to the meso positions of porphyrins often react with neighboring groups, in particular ß-acyl groups to give highly diversified monomeric and dimeric new functionalized porphyrins. The products, whose meso-aryl ring approaches coplanarity with the porphyrin macrocycle, show large shifts of UV-visible absorption bands and various potentialities for building external chelating moieties and assembling oligoporphyrins.

scholarly journals A New Non-Centrosymmetricorganotin (IV) Hybrid Compound C5H14N2 [SnCl6] 2H2O: Crystal Structure And Optical Study Characterization

2021 ◽  
Author(s):  
Nejeh Hannachi ◽  
Thierry ROISNEL ◽  
Faouzi HLEL
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Optical Band Gap ◽  
X Ray Diffraction ◽  
Absorption Bands ◽  
Hybrid Compound ◽  
Visible Absorption ◽  
X Ray ◽  
Uv Visible ◽  
Absorption Measurements

Abstract A new non-centrosymmetricorganotin (IV) hybrid compoundC5H14N2 [SnCl6] 2H2O was determined by single crystal X-ray diffraction at 150(2) K. Its crystal structure was solved by single crystal X-ray diffraction reveling that compound crystallizes in the orthorhombic system with Pbca space group with the following lattice parameters: a = 12.1486 (15) Å, b= 15.4571 (17) Å, c = 16.7610 (18) Å with Z = 8. The bonding between inorganic and organic entities in the compounds is realized by hydrogen bonding O−H…O ,O−H…Cl , NH • • • Cl, N-H…Cl and O−H…Cl. Finally,UV-visible absorption measurements exhibit two absorption bands (226 nm and 262 nm).The optical band gap (Eg) is deduced to be 3.46 Ev.

scholarly journals The UV-visible absorption cross-sections of IONO<sub>2</sub>

2002 ◽  
Vol 2 (3) ◽  
pp. 227-234 ◽  
Author(s):  
J. C. Mössinger ◽  
D. M. Rowley ◽  
R. A. Cox
Keyword(s):  
Cross Sections ◽  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Laser Flash ◽  
Absorption Bands ◽  
Visible Absorption ◽  
Time Resolved ◽  
Model Calculations ◽  
Solar Photolysis ◽  
Uv Visible

Abstract. The UV-visible absorption spectrum of gaseous IONO2 has been measured over the wavelength range 245--415 nm using the technique of laser photolysis with time-resolved UV-visible absorption spectroscopy. IONO2 was produced in situ in the gas phase by laser flash photolysis of NO2/CF3I/N2 mixtures. Post flash spectra were deconvolved to remove contributions to the observed absorption from other reactant and product species. The resulting spectrum attributed to IONO2 consists of several overlapping broad absorption bands. Assuming a quantum yield of unity for IONO2 photolysis, model calculations show that during sunlit hours at noon, 53° N, the first order solar photolysis rate coefficient (J value) for IONO2 is 4.0 x 10-2 s-1.

Ag-Fe Alloy Nanoparticles Embedded in Polyaniline Nanocomposite Thin Films for E. coli Monitoring Sensor

2015 ◽  
Vol 1119 ◽  
pp. 101-105 ◽  
Author(s):  
Huda Abdullah ◽  
Norshafadzila Mohammad Naim ◽  
Noor Azwen Noor Azmy ◽  
Akrajas Ali Umar ◽  
Aidil Abdul Hamid ◽  
...  
Keyword(s):  
Thin Films ◽  
Bimetallic Nanoparticles ◽  
Oxidative Polymerization ◽  
Reduction Process ◽  
Alloy Nanoparticles ◽  
Absorption Bands ◽  
Visible Absorption ◽  
E Coli ◽  
Nanocomposite Thin Films ◽  
Uv Visible

The nanocomposite of polyaniline (PANI) and bimetallic nanoparticles of silver and iron were prepared by the oxidative polymerization of aniline and the reduction process of bimetallic compound with the presence of nitric acid and PVA. The nanocomposite thin films in various compositions were deposited using spin-coating technique. The films were characterized by UV-visible spectroscopy to study the optical and structural properties. The microphotograph from TEM image shows the nanospherical of Ag-Fe alloy particles in 5 – 25 nm diameter size. The sensitivity performance was tested using I-V measurement to obtain the changes of resistivity before and after the incubation with E. coli bacteria in water. UV-visible absorption bands show the single absorbance peak at 422 – 424 nm in each band indicating the Ag-Fe alloy nanoparticles form. I-V characteristic shows the sample which contains Fe-rich Ag-Fe alloy performed high sensitivity on E. coli.

scholarly journals The UV-visible absorption cross-sections of IONO<sub>2</sub>

2002 ◽  
Vol 2 (3) ◽  
pp. 765-788 ◽  
Author(s):  
J. C. Mössinger ◽  
D. M. Rowley ◽  
R. A. Cox
Keyword(s):  
Cross Sections ◽  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Laser Flash ◽  
Absorption Bands ◽  
Visible Absorption ◽  
Time Resolved ◽  
Model Calculations ◽  
Solar Photolysis ◽  
Uv Visible

Abstract. The UV-visible absorption spectrum of gaseous IONO2 has been measured over the wavelength range 245--415 nm using the technique of laser photolysis with time-resolved UV-visible absorption spectroscopy. IONO2 was produced in situ in the gas phase by laser flash photolysis of NO2/CF3I/N2 mixtures. Post-flash spectra were deconvolved to remove contributions to the observed absorption from other reactant and product species. The resulting spectrum attributed to IONO2 consists of several overlapping broad absorption bands. Assuming a quantum yield of unity for IONO2 photolysis, model calculations show that during sunlit hours at noon, 53° N, the first order solar photolysis rate coefficient (J value) for IONO2 is 4.6 x 10-2 s-1.

scholarly journals OS100: A Benchmark Set of 100 Digitized UV-Visible Spectra and Derived Experimental Oscillator Strengths

2021 ◽  
Author(s):  
Astrid Tarleton ◽  
Jorge Garcia-Alvarez ◽  
Anah Wynn ◽  
Cade Awbrey ◽  
Tomas Roberts ◽  
...  
Keyword(s):  
Density Functional ◽  
Oscillator Strengths ◽  
Learning Approaches ◽  
Excitation Energies ◽  
Absorption Bands ◽  
Visible Absorption ◽  
Plain Text ◽  
Solvent Model ◽  
Visible Spectra ◽  
Uv Visible

Excited-state quantum chemical calculations typically report excitation energies and oscillator strengths, ƒ, for each electronic transition. On the other hand, UV-visible spectrophotometric experiments report energy-dependent molar extinction/attenuation coefficients, ε(v), that determine the absorption band line shapes. ε(v) and ƒ are related, but this relation is complicated by various broadening and solvation effects. We fit and integrated experimental UV-visible spectra to obtain ƒexp values for absorption bands and estimated the uncertainty in the fitting. We derived 164 ƒexp values from 100 organic molecules ranging in size from 6-34 atoms. The corresponding computed oscillator strengths (ƒcomp) were obtained with time-dependent density functional theory and a polarizable continuum solvent model. By expressing experimental and computed absorption strengths using a common quantity, we directly compared ƒcomp and ƒexp. While ƒcomp and ƒexp are well correlated (linear regression R2=0. 921), ƒcomp in most cases significantly overestimates ƒexp (regression slope=1.34). The agreement between absolute ƒcomp and ƒexp values was substantially improved by accounting for a solvent refractive index factor, as suggested in some derivations in the literature. The 100 digitized UV-visible spectra are included as plain text files in the supporting information to aid in benchmarking computational or machine-learning approaches that aim to simulate realistic UV-visible absorption spectra.

Improving the electrical and optical properties of C50 fullerene using the Donor-Acceptor groups

2021 ◽  
Author(s):  
Ali Ayoubikaskooli ◽  
Abdol Mohammad Ghaedi ◽  
Hamid Reza Shamlouei ◽  
Yadollah Saghapour
Keyword(s):  
Optical Properties ◽  
Near Infrared ◽  
Infrared Region ◽  
Absorption Bands ◽  
Visible Absorption ◽  
Acceptor Group ◽  
Donor And Acceptor ◽  
Donor Acceptor ◽  
Linear Optical Properties ◽  
Uv Visible

Abstract In this research, the C50 fullerene was employed as the source of the π electrons and the electron donor-acceptor groups were used to enhance its optical properties. Considerable enhancement in its electronic and optical property of as the result of donor and acceptor group presence was observed. For instance, in UV-Visible absorption spectrum, the number of absorption lines significantly increase which may be the relaxation of the electronic transition selection rules. Considerably, the substituted forms of C50, has numbers of absorption bands in near infrared region. The BH2–C50-NCH3Li and NO–C50-NCH3Li molecules have superior improvement in optical properties. Finally, the donor and acceptor groups influence on non-linear optical properties (NLO) of C50 were explored and the considerable improvement in NLO properties of C50 was observed which the NLO improvements for BH2-C50-NCH3Li and NO-C50-CH2Li cases is higher than others.

scholarly journals Theoretical Study of the Absorption Spectrum and the Thermochemistry of the CF3OSO3 Radical

2010 ◽  
Vol 65 (8-9) ◽  
pp. 720-724 ◽  
Author(s):  
Carlos J. Cobos ◽  
Adela E. Croce
Keyword(s):  
Absorption Spectrum ◽  
Density Functional ◽  
Basis Set ◽  
Absorption Bands ◽  
Visible Absorption ◽  
Functional Theory ◽  
Dissociation Enthalpy ◽  
The Density Functional Theory ◽  
Uv Visible ◽  
Experimental Absorption

The UV-visible absorption spectrum of the recently reported CF3OSO3 radical has been studied by using the time-dependent generalization of the density functional theory (TDDFT). For this a set of eleven hybrid functionals combined with the 6-311+G(3df) basis set were employed. The main features of the three experimental absorption bands of CF3OSO3 recorded over the 220 - 530 nm range are well reproduced by the calculations. A dissociation enthalpy for the CF3O-SO3 bond of 19.1 kcal mol−1 is predicted at the BAC-G3MP2//B3LYP/6-311+G(3df) level of theory

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