Substitution effect on the nonradiative decay and trans → cis photoisomerization route: a guideline to develop efficient cinnamate-based sunscreens

2021 ◽  
Author(s):  
Shin-nosuke Kinoshita ◽  
Yu Harabuchi ◽  
Yoshiya Inokuchi ◽  
Satoshi Maeda ◽  
Masahiro Ehara ◽  
...  
Keyword(s):  
Substitution Effect ◽  
Nonradiative Decay

Para-substituted cinnamates are promising sunscreen reagents. They undergo efficient multistep nonradiative decay via the 1nπ* (and/or 3nπ*) and 3ππ* states and finally trans → cis photoisomerization. Para-substitution stabilizes π orbitals and enhances the photoisomerization.

The Character of Low-Lying Excited States of Mixed-Ligand Metal Carbonyls. TD-DFT and CASSCF/CASPT2 Study of [W(CO)4L] (L = ethylenediamine, N,N'-dialkyl-1,4-diazabutadiene) and [W(CO)5L] (L = pyridine, 4-cyanopyridine)

2003 ◽  
Vol 68 (1) ◽  
pp. 89-104 ◽  
Author(s):  
Stanislav Záliš ◽  
Antonín Vlček ◽  
Chantal Daniel
Keyword(s):  
Excited States ◽  
Substitution Effect ◽  
Electronic Transitions ◽  
Ligand Field ◽  
Metal Carbonyls ◽  
Electron Density Redistribution ◽  
Time Resolved ◽  
Model Complex ◽  
Td Dft ◽  
Time Resolved Infrared Spectroscopy

This contribution presents the results of the TD-DFT and CASSCF/CASPT2 calculations on [W(CO)4(MeDAB)] (MeDAB = N,N'-dimethyl-1,4-diazabutadiene), [W(CO)4(en)] (en = ethylenediamine), [W(CO)5(py)] (py = pyridine) and [W(CO)5(CNpy)] (CNpy = 4-cyanopyridine) complexes. Contrary to the textbook interpretation, calculations on the model complex [W(CO)4(MeDAB)] and [W(CO)5(CNpy)] show that the lowest W→MeDAB and W→CNpy MLCT excited states are immediately followed in energy by several W→CO MLCT states, instead of ligand-field (LF) states. The lowest-lying excited states of [W(CO)4(en)] system were characterized as W(COeq)2→COax CT excitations, which involve a remarkable electron density redistribution between axial and equatorial CO ligands. [W(CO)5(py)] possesses closely-lying W→CO and W→py MLCT excited states. The calculated energies of these states are sensitive to the computational methodology used and can be easily influenced by a substitution effect. The calculated shifts of [W(CO)4(en)] stretching CO frequencies due to excitation are in agreement with picosecond time-resolved infrared spectroscopy experiments and confirm the occurrence of low-lying M→CO MLCT transitions. No LF electronic transitions were found for either of the complexes studied in the region up to 4 eV.

Vehicle Miles Traveled in Multivehicle Households

2005 ◽  
Vol 1926 (1) ◽  
pp. 198-205
Author(s):  
Somchai Pathomsiri ◽  
Ali Haghani ◽  
Paul M. Schonfeld
Keyword(s):  
Least Squares Method ◽  
Substitution Effect ◽  
Mitigation Measures ◽  
Vehicle Miles Traveled ◽  
Emission Mitigation ◽  
Conservation Policies ◽  
Multiple Vehicles ◽  
Single Vehicle ◽  
Household Travel ◽  
Behavior Shift

Vehicle miles traveled (VMT) is an important factor in the development of transportation plans, emission mitigation measures, and energy conservation policies. Therefore, estimation of VMT is a crucial task supporting such plans and policies. This research addresses the estimation of VMT in households owning multiple vehicles. This sector is expected to use vehicles differently from single-vehicle households because usage of any vehicle may depend on usage of other vehicles. Previous studies concluded that there is a substitution effect between usages of two vehicles (i.e., greater usage of one vehicle lessens usage of the other). In view of more recent changes in sociodemographic structure, the problem was revisited with the 2001 National Household Travel Survey database. The proposed VMT model is a system of simultaneous equations. Each equation explains the VMT for one of the household's vehicles. The three-stage least-squares method was used to estimate the coefficients. A case study of two-vehicle households was investigated. The resulting model shows that VMT can be explained by variables such as the vehicle's newness, number of potential car users in a household, and household income. Surprisingly, the results show not a substitution effect but a spilling effect. The VMT of the first vehicle does not depend on how much the second vehicle is driven. However, increased use of the first vehicle tends to spill over and increase the use of the second one. Some explanation of this behavior shift is provided.

FET performance and substitution effect on 2,6-dithienylanthracene devices prepared by photoirradiation of their diketone precursors

2012 ◽  
Vol 48 (90) ◽  
pp. 11136 ◽  
Author(s):  
Hiroko Yamada ◽  
Chika Ohashi ◽  
Tatsuya Aotake ◽  
Shuhei Katsuta ◽  
Yoshihito Honsho ◽  
...  
Keyword(s):  
Substitution Effect

scholarly journals NMR spectroscopic investigation of benzothiazolylacetonitrile azo dyes: CR7 substitution effect and semiempirical study

2021 ◽  
Vol 3 ◽  
pp. 100088
Author(s):  
H.M. Alsoghier ◽  
M. Abdellah ◽  
H.M. Rageh ◽  
H.M.A. Salman ◽  
M.A. Selim ◽  
...  
Keyword(s):  
Azo Dyes ◽  
Spectroscopic Investigation ◽  
Substitution Effect

Regulating the magnetic dynamics of mononuclear β-diketone Dy(iii) single-molecule magnets through the substitution effect on capping N-donor coligands

2021 ◽  
Vol 50 (6) ◽  
pp. 2102-2111
Author(s):  
Jing Xi ◽  
Xiufang Ma ◽  
Peipei Cen ◽  
Yuewei Wu ◽  
Yi-Quan Zhang ◽  
...  
Keyword(s):  
Ab Initio ◽  
Single Molecule ◽  
Substitution Effect ◽  
Single Molecule Magnets ◽  
Magnetic Dynamics ◽  
Magnetic Investigation

Substituent change modulates the coordination symmetries and magnetic dynamics of five mononuclear β-diketonate-Dy(iii) complexes with capping N-donor coligands, which is studied by the combination of magnetic investigation and ab initio calculation.

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