scholarly journals Optical absorption and electronic spectra of chlorophylls a and b

RSC Advances ◽  
2016 ◽  
Vol 6 (111) ◽  
pp. 109778-109785 ◽  
Author(s):  
Leila Hedayatifar ◽  
Elnaz Irani ◽  
Mahmood Mazarei ◽  
Soroush Rasti ◽  
Yavar T. Azar ◽  
...  
Keyword(s):  
Optical Absorption ◽  
Electronic Properties ◽  
Absorption Spectra ◽  
Electronic Spectra ◽  
Green Plants ◽  
Chlorophylls A And B ◽  
Optical And Electronic Properties

We report optical and electronic properties of the two main chlorophylls in green plants, namely, chlorophylls a and b. We estimate the electric moments of these molecules and study absorption spectra of the chlorophylls.

Intermolecular interactions and electronic properties in phosphino-(oligothiophene) palladium(II) and platinum(II) complexes

2007 ◽  
Vol 85 (5) ◽  
pp. 383-391 ◽  
Author(s):  
Tracey L Stott ◽  
Michael O Wolf ◽  
Brian O Patrick
Keyword(s):  
Solid State ◽  
Metal Complexes ◽  
Electronic Properties ◽  
Crystal Structures ◽  
Structural Properties ◽  
Absorption Spectra ◽  
Intermolecular Interactions ◽  
Electronic Spectra ◽  
X Ray ◽  
Π Stacking

A series of Pt(II) and Pd(II) complexes containing diphenylphosphino-substituted oligothiophene ligands ranging from 1 to 3 thiophene rings in length have been prepared. Crystal structures of four of these complexes were determined via single X-ray crystal diffraction and the solid-state packing arrangements found to vary with both the metal and the thiophene-containing ligand. In some cases, π-stacking between thiophene rings are found for the oligothiophene ligands. Solution and solid-state absorption spectra of these complexes are reported.Key words: oligothiophenes, metal complexes, structural properties, electronic spectra.

scholarly journals Photoelectrochemistry of Ferrites: Theoretical Predictions vs. Experimental Results

2020 ◽  
Vol 234 (4) ◽  
pp. 719-776 ◽  
Author(s):  
Anna C. Ulpe ◽  
Katharina C.L. Bauerfeind ◽  
Luis I. Granone ◽  
Arsou Arimi ◽  
Lena Megatif ◽  
...  
Keyword(s):  
Optical Absorption ◽  
Electronic Properties ◽  
Absorption Spectra ◽  
Raman Spectra ◽  
First Principles ◽  
Experimental Results ◽  
Atomic Scale ◽  
Optical Absorption Spectra ◽  
Photoelectrochemical Activity

AbstractThis paper gives an overview about recent theoretical and experimental work on electronic and optical properties of spinel ferrites MFe2O4. These compounds have come into focus of research due to their possible application as photocatalyst material for photoelectrochemical water splitting. The theoretical background of state-of-the-art quantum-chemical approaches applied for predicting electronic and optical band gaps, absolute band positions, optical absorption spectra, dielectric functions and Raman spectra, is briefly reviewed. Recent applications of first-principles methods on magnetic and electronic properties of ferrites with M = Mg and the first row of subgroup elements Sc to Zn are presented, where it is shown that the fundamental band gap is strongly dependent on the spin state and the degree of inversion of the spinel structure. The observed variation of electronic properties may serve as an explanation for the large scattering of experimental results. The exchange of M and Fe cations has also a pronounced effect on the Raman spectra of ferrites, which is analyzed at atomic scale from first principles. Calculated optical absorption spectra of ferrites are compared to experimental spectra. The electronic nature of the first excitations and the role of oxygen vacancies are discussed. For the calculation of absolute band positions, which have a significant impact on the photoelectrochemical activity of the ferrites, models of the most stable ferrite surfaces are developed that take into account their polar nature and the interaction with the solvent. Theoretically predicted valence and conduction band edges are compared to results from electrochemical measurements. The role of cation exchange on the surface electronic structure is investigated both theoretically and experimentally.

scholarly journals Taking Lanthanides out of Isolation: Tuning the Optical Properties of Metal-Organic Frameworks

2020 ◽  
Author(s):  
Samantha L. Anderson ◽  
Davide Tiana ◽  
Christopher Ireland ◽  
Gloria Capano ◽  
Maria Fumanal ◽  
...  
Keyword(s):  
Optical Absorption ◽  
Electronic Properties ◽  
Rational Design ◽  
Computational Study ◽  
Water Solution ◽  
Metal Organic Frameworks ◽  
Visible Region ◽  
Co Catalysts ◽  
Optical And Electronic Properties ◽  
Metal Organic

<div>Metal organic frameworks (MOFs) are increasingly used in applications that rely on the optical and electronic properties of these materials. These applications require a fundamental understanding on how the structure of these materials, and in particular the electronic interactions of the metal node and organic linker, determines these properties. </div><div><br></div><div>Herein, we report a combined experimental and computational study on two families of lanthanide-based MOFs: Ln-SION-1 and Ln-SION-2. Both comprise the same metal and ligand but with differing structural topologies. In the Ln-SION-2 series the optical absorption is dominated by the ligand and using different lanthanides has no impact on the absorption spectrum. The Ln-SION-1 series shows a completely different behavior in which the ligand and the metal node do interact electronically. By changing the lanthanide in Ln-SION-1, we were able to tune the optical absorption from the UV region to absorption that includes a large part of the visible region. For the early lanthanides we observe intraligand (electronic) transitions in the UV region, while for the late lanthanides a new band appears in the visible. DFT calculations showed that the new band in the visible originates in the spatial orbital overlap between the ligand and metal node. Our quantum calculations indicated that Ln-SION-1 with late lanthanides might be (photo)conductive. Experimentally, we confirm that these materials are weakly conductive and that with an appropriate co-catalysts they can generate hydrogen from a water solution using visible light. Our experimental and theoretical analysis provides fundamental insights for the rational design of Ln-MOFs with the desired optical and electronic properties.</div>

Electronic properties and geometric structures of Li4H and Li9H from optical absorption spectra

1995 ◽  
Vol 102 (7) ◽  
pp. 2727-2736 ◽  
Author(s):  
B. Vezin ◽  
Ph. Dugourd ◽  
C. Bordas ◽  
D. Rayane ◽  
M. Broyer ◽  
...  
Keyword(s):  
Optical Absorption ◽  
Electronic Properties ◽  
Absorption Spectra ◽  
Optical Absorption Spectra ◽  
Geometric Structures

scholarly journals Taking Lanthanides out of Isolation: Tuning the Optical Properties of Metal-Organic Frameworks

2020 ◽  
Author(s):  
Samantha L. Anderson ◽  
Davide Tiana ◽  
Christopher Ireland ◽  
Gloria Capano ◽  
Maria Fumanal ◽  
...  
Keyword(s):  
Optical Absorption ◽  
Electronic Properties ◽  
Rational Design ◽  
Computational Study ◽  
Water Solution ◽  
Metal Organic Frameworks ◽  
Visible Region ◽  
Co Catalysts ◽  
Optical And Electronic Properties ◽  
Metal Organic

<div>Metal organic frameworks (MOFs) are increasingly used in applications that rely on the optical and electronic properties of these materials. These applications require a fundamental understanding on how the structure of these materials, and in particular the electronic interactions of the metal node and organic linker, determines these properties. </div><div><br></div><div>Herein, we report a combined experimental and computational study on two families of lanthanide-based MOFs: Ln-SION-1 and Ln-SION-2. Both comprise the same metal and ligand but with differing structural topologies. In the Ln-SION-2 series the optical absorption is dominated by the ligand and using different lanthanides has no impact on the absorption spectrum. The Ln-SION-1 series shows a completely different behavior in which the ligand and the metal node do interact electronically. By changing the lanthanide in Ln-SION-1, we were able to tune the optical absorption from the UV region to absorption that includes a large part of the visible region. For the early lanthanides we observe intraligand (electronic) transitions in the UV region, while for the late lanthanides a new band appears in the visible. DFT calculations showed that the new band in the visible originates in the spatial orbital overlap between the ligand and metal node. Our quantum calculations indicated that Ln-SION-1 with late lanthanides might be (photo)conductive. Experimentally, we confirm that these materials are weakly conductive and that with an appropriate co-catalysts they can generate hydrogen from a water solution using visible light. Our experimental and theoretical analysis provides fundamental insights for the rational design of Ln-MOFs with the desired optical and electronic properties.</div>

Pressure-dependent modifications in the optical and electronic properties of Fe(IO3)3: The role of Fe 3d and I 5p lone-pair electrons

2021 ◽  
Author(s):  
Akun Liang ◽  
Placida Rodríguez-Hernandez ◽  
Alfonso Munoz ◽  
Saqib Raman ◽  
Alfredo Segura ◽  
...  
Keyword(s):  
Optical Absorption ◽  
Band Gap ◽  
Electronic Properties ◽  
Lone Pair ◽  
Band Gap Energy ◽  
Gap Energy ◽  
Optical And Electronic Properties ◽  
Indirect Band Gap ◽  
Lone Pair Electrons

We have determined by means of optical-absorption experiments that Fe(IO3)3 is an indirect band-gap material with a band-gap energy of 2.1 eV. This makes this compound the iodate with the...

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