scholarly journals Level of Theory and Solvent Effects on DASA Absorption Properties Prediction: Comparing TD-DFT, CASPT2 and NEVPT2

Materials ◽  
2017 ◽  
Vol 10 (9) ◽  
pp. 1025 ◽  
Author(s):  
Cristina García-Iriepa ◽  
Marco Marazzi
Keyword(s):  
Solvent Effects ◽  
Absorption Properties ◽  
Td Dft

Solvent Effects on the UV–Vis Absorption Properties and Tautomerism of N-Confused Tetraphenylporphyrin

2015 ◽  
Vol 80 (21) ◽  
pp. 11031-11038 ◽  
Author(s):  
Elvin A. Alemán ◽  
Jojo Joseph ◽  
David A. Modarelli
Keyword(s):  
Solvent Effects ◽  
Absorption Properties

scholarly journals TD-DFT Prediction of the Intermolecular Charge-Transfer UV-Vis Spectra of Viologen Salts in Solution

2020 ◽  
Vol 10 (22) ◽  
pp. 8108
Author(s):  
Giacomo Saielli
Keyword(s):  
Charge Transfer ◽  
Solvent Effects ◽  
Polar Solvent ◽  
Essential Feature ◽  
Visible Range ◽  
Absorption Bands ◽  
Chemical Methods ◽  
Quantum Chemical Methods ◽  
Td Dft ◽  
Very High

The absorption spectrum of viologen salts in a medium or low polar solvent is an essential feature that influences all its “chromic” applications, whether we are considering thermochromic, electrochromic, photochromic or chemochromic devices. The prediction by quantum chemical methods of such absorption bands, typically observed in the visible range and due to charge transfer (CT) phenomena, is a very challenging problem due to strong solvent effects influencing both the geometry and the electronic transitions. Here we present a computational protocol based on DFT to predict with very high accuracy the absorption maxima of the CT bands of a series of viologen salts in solvents of low and medium polarity. The calculations also allow a clear dissection of the solvent effects, direct and indirect, and orbital contributions to the CT band.

Solvent effects on static polarizability, static first hyperpolarizability and one- and two-photon absorption properties of functionalized triply twisted Möbius annulenes: a DFT study

2016 ◽  
Vol 18 (31) ◽  
pp. 21833-21842 ◽  
Author(s):  
Md Mehboob Alam ◽  
Varun Kundi ◽  
Pompozhi Protasis Thankachan
Keyword(s):  
Solvent Effects ◽  
Photon Absorption ◽  
Dft Study ◽  
First Hyperpolarizability ◽  
Absorption Properties ◽  
Static Polarizability ◽  
Two Photon Absorption ◽  
Two Photon

Solvent effects on the polarizability (α), static first hyperpolarizability (β) and one- and two-photon absorption (OPA and TPA) properties of triply twisted Möbius annulenes.

Solvent Effects on C60 Excited State Cross Sections

1994 ◽  
Vol 374 ◽  
Author(s):  
Daniel G. McLean ◽  
Donna M. Brandelik ◽  
Mark C. Brant ◽  
Richard L. Sutherland ◽  
Lynn Frock
Keyword(s):  
Excited State ◽  
Cross Section ◽  
Cross Sections ◽  
Solvent Effects ◽  
Nonlinear Absorption ◽  
Equation System ◽  
Survey Study ◽  
Absorption Properties ◽  
Absorption Measurements ◽  
Initial Transmission

AbstractA survey study of solvent effects on the linear and nonlinear absorption properties of C60 has been done. The nonlinear absorption measurements are done at 694 nm with a Q-switched Nd:YAG pumped dye laser. In conjunction with this study a three level rate equation system has been solved analytically and the model results used to extract effective excited state cross sections. A difference and a ratio are calculated from the effective excited state cross section and the ground state cross section. The analysis demonstrates that it is this difference and the initial transmission which determine the critical fluence for the onset of nonlinear absorption. The saturation behavior is determined by the ratio of the cross sections and the initial transmission. Based on these findings C60 is shown to have some of the highest reported nonlinear absorption properties at 694 nm. The effective excited state cross sections at 694 nm are reported for the solutions and correlations to the solvent types demonstrated.

Aggregation of squaraine dyes: Structure–property relationships and solvent effects

1995 ◽  
Vol 73 (10) ◽  
pp. 1605-1615 ◽  
Author(s):  
Andrew J. McKerrow ◽  
Erwin Buncel ◽  
Peter M. Kazmaier
Keyword(s):  
Solvent Effects ◽  
Absorption Maximum ◽  
Type A ◽  
Spectral Features ◽  
Type B ◽  
Structure Property ◽  
Absorption Properties ◽  
Lb Films ◽  
Squaraine Dyes ◽  
Structure Property Relationships

In characterizing the UV–visible absorption properties of a series of seven anilino class squaraine dyes in dimethyl sulfoxide (DMSO) – water mixtures, spectral features characteristic of aggregation were observed. These included hypsochromic and hypochromic shifts of the absorption maximum, relative to the nonassociated state of these dyes. Previously aggregation of this class of squaraine dyes had only been reported in studies of Langmuir–Blodgett (LB) films prepared with squaraine dyes. In the present study two distinctly different and novel solution dye aggregates, designated as type A and type B, were identified on the basis of their characteristic absorption properties. The type A aggregate was characterized by an absorption maximum that was hypsochromically and hypochromically shifted, in comparison with that of the nonassociated dyes, and had a secondary absorption occurring at approximately the same wavelength at which nonassociated squaraine dyes absorb. These spectral features are believed to be the result of a "face-to-face" alignment of molecules in the aggregate. The type B aggregate featured a broad absorption typically from 525 to 700 nm. Based on similarities between the spectral features of type B aggregates and LB films of surfactant squaraines, the alignment of molecules in the solution aggregate was believed to be such that the electron-deficient squarylium moieties interacted with the electron-rich dialkylamino phenyl moieties. Certain squaraine dyes that were investigated as part of this study were found to form both type A and type B aggregates, depending upon the composition of the DMSO–water medium. Typically, the type A aggregate formed preferentially in media of intermediate DMSO content (50–70% DMSO) and the type B aggregate in more water-rich media (<20% DMSO). In the intervening region it was possible to monitor spectroscopically a dynamic conversion from the type B aggregate to the type A aggregate. An examination of structure–property relationships indicated that dyes with less hydrophobic N-alkyl substituents formed only type A aggregates. Squaraine dyes with more hydrophobic N-alkyl substituents were found to form type B aggregates in water and type A aggregates in some DMSO–water mixtures. A model of squaraine aggregation was proposed in which the type A squaraine aggregate was "thermodynamically" preferred while the type B aggregate was "kinetically" preferred. The stability of the type B aggregate was proposed to be enhanced by increasing hydrophobicity of the N-alkyl substituents and decreased by increasing amounts of DMSO in the solvent system. Keywords: squaraine dyes, aggregation, crystallochromy, solvent effects.

Sign in / Sign up

Export Citation Format

Share Document