scholarly journals Theoretical Study on Structure and Electronic Properties of 4H-Cyclopenta[2,1-b,3;4-b’]dithiopene S-oxide and Its CCl2 and CF2 Bridged Derivatives

2015 ◽  
Vol 15 (1) ◽  
pp. 93-100 ◽  
Author(s):  
Banjo Semire ◽  
Olusegun Ayobami Odunola
Keyword(s):  
Density Functional Theory ◽  
Thermodynamic Properties ◽  
Quantum Chemical ◽  
Density Functional ◽  
Theoretical Study ◽  
Functional Theory ◽  
Td Dft ◽  
Moller Plesset ◽  
Semi Empirical ◽  
Good Agreement

Quantum chemical calculations using semi-empirical, ab initio, density functional theory (DFT) and Møller plesset (MP2) methods were performed on 4H-Cyclopenta[2,1-b,3;4-b’]dithiopene S-oxide derivatives (i.e. bridged dithiophene S-oxides, BTOs). The geometries, stabilities, electronic and thermodynamic properties of the compounds were studied. The thermodynamic parameters calculated at PM3 were in good agreement with those calculated at B3LYP/6-31G(d) level. The band gap energies calculated at B3LYP/6-31G(d) level for the BTOs were lower than the un-substituted trithiophene but higher than 4H-Cyclopenta[2,1-b,3;4-b’]dithiopene. The absorption λmax calculated using TD-DFT was shifted to longer wavelength by successive replacement of methylene hydrogens of BTO by chlorine and fluorine atoms.

scholarly journals STRUCTURAL AND ELECTRONIC PROPERTIES OF BRIDGED BITHIOPHENE S-OXIDES (BTO) WITH S, S=O, O, SiH2 and BH2 BRIDGE: SEMI-EMPIRICAL AND AB INITIO STUDY

2010 ◽  
Vol 18 (18) ◽  
pp. 1-10
Author(s):  
Banjo Semire ◽  
Isaiah Ajibade Adejoro ◽  
Olusegun Ayobami Odunola
Keyword(s):  
Density Functional Theory ◽  
Thermodynamic Properties ◽  
Ab Initio ◽  
Density Functional ◽  
Ab Initio Study ◽  
Empirical Methods ◽  
Functional Theory ◽  
Structural And Electronic Properties ◽  
Semi Empirical ◽  
Good Agreement

In this paper, we theoretically studied the geometries, stabilities, electronic and thermodynamic properties of bridged bithiophene S-oxide (BTO-X) derivates (with X = BH2, SiH2, S, S=O, and O) by using semi-empirical methods, ab-initio, and Density functional theory. The geometries and thermodynamic parameters calculated by PM3 were in good agreement with that of B3LYP/6-31G(d). The bandgap calculated by B3LYP/6-31G(d) ranged from 3.94eV (BTO-O)-3.16eV (BTO-BH2). The absorption λmax calculated suing B3LYP/6-31G(d) shifted to longer wavelength with X=BH2, SiH2, and S=O due to enhancement of π-conjugated system whereas, BTO-S and BTO-O shifted to shorter wavelengths as compared to dimmer thiophene S-oxide (2TO).

scholarly journals ENERGIES AND VIBRATIONAL MODES OF SPECIES FORMED BY DEHYDROGENATION OF CH4 IN PRESENCE OF O2 OVER Cr2O3(0001)

Anales AFA ◽  
2021 ◽  
Vol 32 (3) ◽  
pp. 83-87
Author(s):  
S.N. Hernández Guiance ◽  
◽  
I.D. Coria ◽  
I.M. Irurzun ◽  
◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Theoretical Study ◽  
Experimental Methods ◽  
Vibrational Modes ◽  
Functional Theory ◽  
Methanol Formation ◽  
Dissociative States ◽  
Dissociative State ◽  
Good Agreement

In this work we perform a theoretical study of dehydrogenation process of CH4 on O2– in both molecular and dissociative states - previously adsorbed on Cr2O3(0001). Calculations are based on Density Functional Theory (DFT). The results show the methanol formation form the adsorption of CH4 on O2 in dissociative state with a formationenergy5:14 eV. Also formaldehyde was formed by the reaction of CH2with molecular O2(Eads=6:09 eV) and dioxymethylene by the reaction of CH2with O2 previously adsorbed in dissociative state on Cr2O3(0001), withEads=8:17 eV. Finally, the vibrational modes found by DFT for each of the species were compared, which are in good agreement with those of reference bibliography. This allows us to support the values found both by technical calculations and by experimental methods.

scholarly journals First principles calculations of the electronic and dielectric properties of λ-Ta2O5

TecnoLógicas ◽  
2018 ◽  
Vol 21 (43) ◽  
pp. 43-52 ◽  
Author(s):  
Camilo Valencia-Balvín ◽  
Santiago Pérez-Walton ◽  
Jorge M. Osorio-Guillén
Keyword(s):  
Density Functional Theory ◽  
First Principles ◽  
Density Functional ◽  
Theoretical Study ◽  
Wide Bandgap ◽  
First Principles Calculations ◽  
Functional Theory ◽  
Wide Bandgap Semiconductor ◽  
Exchange Correlation ◽  
Good Agreement

Ta2O5 is a wide-bandgap semiconductor that offers interesting applications in microwavecommunications, mainly related to the manufacture of filters and resonators whosesize is inversely proportional to the dielectric constant of the material. For that reason, inthis work we present a theoretical study, based on density functional theory (using PBEsoland hybrid HSE06 exchange-correlation functionals), of the electronic and dielectricproperties of the orthorhombic model -Ta2O5. We found that this model has a direct gap of2.09 and 3.7 eV with PBEsol and HSE06, respectively. Furthermore, the calculated staticdielectric constant, 51, is in good agreement with the reported values of other phases of thissemiconductor.

scholarly journals Theoretical Study of Divalent Bis(Pentaisopropylcyclopentadienyl) Actinocenes

2019 ◽  
Author(s):  
Jason Yu ◽  
Filipp Furche
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Theoretical Study ◽  
Ground States ◽  
Functional Theory ◽  
Reduction Potentials ◽  
Td Dft ◽  
Mixed Ground ◽  
Divalent Lanthanide ◽  
Linear Coordination

The existence of divalent bis(pentaisopropylcyclopentadienyl) actinocene compounds, An(CpiPr5)2 for An = (Th, U, Pu, Am, Bk, No, Lr), is assessed by density functional theory (DFT) calculations with scalar-relativistic small core pseudopotentials. The calculations predict ground states with significant 6d occupation for Th, U, and Lr, whereas Am, Bk, and No exhibit 5f ground states. A mixed ground state with predominant 5f character is found for Pu. The complexes exhibit a linear coordination geometry and high S10 symmetry except for Pu(CpiPr5)2 and Am(CpiPr5)2, which are found to be bent by 11 and 12 degrees , respectively. Absorption spectra are simulated with time-dependent density functional theory (TD-DFT) and compared to experimental spectra of known tris(C4H4SiMe3) and tris(C5H3(SiMe3)2) compounds [M. E. Fieser et al., J. Am. Chem. Soc. 2015, 137, 369-382] as well as recently synthesized divalent lanthanide analogs Dy(CpiPr5)2 and Tb(CpiPr5)2 [C. Gould et al., J. Am. Chem. Soc. 2019, accepted]. Thermodynamic stability is assessed by calculation of adiabatic reduction potentials of the trivalent precursors [An(CpiPr5 )2] +, and the feasibility of further reduction to obtain as yet unknown monovalent molecular actinide complexes is discussed. <br>

scholarly journals Theoretical Study of Divalent Bis(Pentaisopropylcyclopentadienyl) Actinocenes

2019 ◽  
Author(s):  
Jason Yu ◽  
Filipp Furche
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Theoretical Study ◽  
Ground States ◽  
Functional Theory ◽  
Reduction Potentials ◽  
Td Dft ◽  
Mixed Ground ◽  
Divalent Lanthanide ◽  
Linear Coordination

The existence of divalent bis(pentaisopropylcyclopentadienyl) actinocene compounds, An(CpiPr5)2 for An = (Th, U, Pu, Am, Bk, No, Lr), is assessed by density functional theory (DFT) calculations with scalar-relativistic small core pseudopotentials. The calculations predict ground states with significant 6d occupation for Th, U, and Lr, whereas Am, Bk, and No exhibit 5f ground states. A mixed ground state with predominant 5f character is found for Pu. The complexes exhibit a linear coordination geometry and high S10 symmetry except for Pu(CpiPr5)2 and Am(CpiPr5)2, which are found to be bent by 11 and 12 degrees , respectively. Absorption spectra are simulated with time-dependent density functional theory (TD-DFT) and compared to experimental spectra of known tris(C4H4SiMe3) and tris(C5H3(SiMe3)2) compounds [M. E. Fieser et al., J. Am. Chem. Soc. 2015, 137, 369-382] as well as recently synthesized divalent lanthanide analogs Dy(CpiPr5)2 and Tb(CpiPr5)2 [C. Gould et al., J. Am. Chem. Soc. 2019, accepted]. Thermodynamic stability is assessed by calculation of adiabatic reduction potentials of the trivalent precursors [An(CpiPr5 )2] +, and the feasibility of further reduction to obtain as yet unknown monovalent molecular actinide complexes is discussed. <br>

Theoretical Study of Adsorption of Solriamfetol Drug on Surface of the B12N12 Fullerene: A DFT/TD-DFT Approach

2020 ◽  
Vol 17 ◽  
Author(s):  
Hooriye Yahyaei ◽  
Shamsa Sharifi ◽  
Siyamak Shahab ◽  
Masoome Sheikhi ◽  
Mahin Ahmadianarog
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Theoretical Study ◽  
Drug Carrier ◽  
Functional Theory ◽  
Adsorption Effect ◽  
Excessive Sleepiness ◽  
Donor And Acceptor ◽  
Td Dft ◽  
First Time

For the first time in the present study, we studied the adsorption effect of the Solriamfetol (SOF) on the electronic and optical properties of B12N12 fullerene using density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations with the M062X/6-311++G(d,p) level of theory in the solvent water. The calculated adsorp-tion energies of SOF drug with the B12N12 fullerene were computed at T= 298.15 K with the M062X functional. The UV/Vis absorption spectra were computed and investigated for study the significant changes happening in interactions between SOF and B12N12 fullerene. The IR spectra also were calculated and investigated. The calculated results indicate that the adsorption of the SOF drug from its internal NH2 group on the B12N12 fullerene (configuration B) has the most chemical stability rather than configuration A and C. According to the NBO results, the SOF molecule and B12N12 fullerene identify as both electrons donor and acceptor at the complexes B12N12-SOF. On the other hand, the charge transfer is occurred between the bonding, antibonding or nonbonding orbitals in the SOF drug and B12N12 fullerene. It is found that the applied B12N12 fullerene can be suitable as a drug carrier for the delivery of SOF as drug for treatment of excessive sleepiness.

Second order hyperpolarizability of triphenylamine based organic sensitizers: a first principle theoretical study

RSC Advances ◽  
2016 ◽  
Vol 6 (79) ◽  
pp. 75242-75250 ◽  
Author(s):  
M. Prakasam ◽  
P. M. Anbarasan
Keyword(s):  
Density Functional Theory ◽  
Ground State ◽  
Density Functional ◽  
Theoretical Study ◽  
Time Dependent ◽  
First Principle ◽  
Functional Theory ◽  
Metal Free ◽  
Td Dft ◽  
Organic Sensitizers

Designed metal-free dyes have been investigated by Density Functional Theory (DFT) and Time-Dependent DFT (TD-DFT) to evaluate the ground state and excited state geometries of triphenylamine-based organic sensitizers.

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