Semi-Empirical Calculations and Measurements of Modified Carbocyanines Optical Properties

AbstractWe report semi-empirical calculations of modified 3,3'-diethylthiacyanine iodide (DTC1), 3,3'-diethylthiacarbocyanine iodide (DTC3) and 3,3'-diethylthiadicarbocyanine iodide (DTC5), particularly with halogen substitution at the meso position in the polymethine bridge. Primarily we investigate geometrical changes and infer spectral trends from the molecular orbital levels. The semi-empirical calculations for the unsubstituted DTC3 agree well with an ab initio Hartree-Fock result. In all molecules multiple conformations are examined. Significant changes in dipole moments are noted between the cis and trans forms. Calculated electronic spectra at the CI singles level are compared to the measured spectra with reasonable agreement. Halogenation effects show a rotation of the benzthiazole groups out of planarity. We draw conclusions about consequent effects on solubility and excited state spectral changes.

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Calculations of Surface Structure for SrTiO3 Perovskite

MRS Proceedings ◽

10.1557/proc-671-q9.1 ◽

2001 ◽

Vol 672 ◽

Author(s):

E. Heifetsa ◽

R.I. Eglitisb ◽

E.A. Kotomin ◽

G. Borstelb

Keyword(s):

Ab Initio ◽

Density Functional ◽

Dipole Moments ◽

Surface Relaxation ◽

Surface Layers ◽

Functional Theory ◽

Near Surface ◽

Hartree Fock ◽

Semi Empirical

ABSTRACTWe present and discuss results of the calculations for SrTiO3 (100) surface relaxation with different terminations (SrO and TiO2) using a semi-empirical shell model (SM) as well as abinitio methods based on Hartree-Fock (HF) and Density Functional Theory (DFT) formalisms. Using the SM, the positions of atoms in 16 near-surface layers placed atop a slab of rigid ions are optimized. This permits us determination of surface rumpling and surfaceinduced dipole moments (polarization) for different terminations. We also compare results of the ab initio calculations based on both HF with the DFT-type electroncorrelation corrections, several DFT with different exchange-correlation functionals, and hybrid exchange techniques. OurSM results for the (100) surfaces are in a good agreement with both our ab initio calculations and LEED experiments.

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Relation between Magnetic, Spectroscopic and Structural Properties of Binuclear Copper(II) Complexes of Pentadentate Schiff-base Ligand, Semi-empirical and ab-initio Calculations

Zeitschrift für Naturforschung A ◽

10.1515/zna-2003-5-620 ◽

2003 ◽

Vol 58 (5-6) ◽

pp. 363-372 ◽

Cited By ~ 12

Author(s):

Y. Elerman ◽

H. Kara ◽

A. Elmali

Keyword(s):

Ab Initio ◽

Coupling Constants ◽

Antiferromagnetic Coupling ◽

X Ray Diffraction ◽

Hartree Fock ◽

Ligand Orbital ◽

Rhf Calculations ◽

The Difference ◽

Semi Empirical

The synthesis and characterization of [Cu2(L1)(3,5 prz)] (L1=1,3-Bis(2-hydroxy-3,5-chlorosalicylideneamino) propan-2-ol) 1 and of [Cu2(L2)(3,5 prz)] (L2=1,3-Bis(2-hydroxy-bromosalicylideneamino) propan-2-ol) 2 are reported. The compounds were studied by elemental analysis, infrared and electronic spectra. The structure of the Cu2(L1)(3,5 prz)] complex was determined by x-ray diffraction. The magnetochemical characteristics of these compounds were determined by temperaturedependent magnetic susceptibility measurements, revealing their antiferromagnetic coupling. The superexchange coupling constants are 210 cm−1 for 1 and 440 cm−1 for 2. The difference in the magnitude of the coupling constants was explained by the metal-ligand orbital overlaps and confirmed by ab-initio restricted Hartree-Fock (RHF) calculations. In order to determine the nature of the frontier orbitals, Extended Hückel Molecular Orbital (EHMO) calculations are also reported.

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ChemInform Abstract: Dispersion of Linear and Nonlinear Optical Properties of Benzene: An ab initio Time-Dependent Coupled-Perturbed Hartree-Fock Study.

ChemInform ◽

10.1002/chin.199207032 ◽

2010 ◽

Vol 23 (7) ◽

pp. no-no

Author(s):

S. P. KARNA ◽

G. B. TALAPATRA ◽

P. N. PRASAD

Keyword(s):

Optical Properties ◽

Ab Initio ◽

Nonlinear Optical ◽

Nonlinear Optical Properties ◽

Time Dependent ◽

Hartree Fock ◽

Linear And Nonlinear

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Density functional tight binding: values of semi-empirical methods in an ab initio era

Physical Chemistry Chemical Physics ◽

10.1039/c4cp00908h ◽

2014 ◽

Vol 16 (28) ◽

pp. 14368-14377 ◽

Cited By ~ 75

Author(s):

Qiang Cui ◽

Marcus Elstner

Keyword(s):

Density Functional Theory ◽

Ab Initio ◽

Density Functional ◽

Tight Binding ◽

Empirical Methods ◽

Functional Theory ◽

Hartree Fock ◽

Semi Empirical

Semi-empirical (SE) methods are derived from Hartree–Fock (HF) or Density Functional Theory (DFT) by neglect and approximation of electronic integrals.

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Nonlinear optical properties of novel thiophene derivatives: Experimental and ab initio time‐dependent coupled perturbed Hartree–Fock studies

The Journal of Chemical Physics ◽

10.1063/1.465398 ◽

1993 ◽

Vol 99 (12) ◽

pp. 9984-9993 ◽

Cited By ~ 21

Author(s):

Shashi P. Karna ◽

Yue Zhang ◽

Marek Samoc ◽

P. N. Prasad ◽

Bruce A. Reinhardt ◽

...

Keyword(s):

Optical Properties ◽

Ab Initio ◽

Nonlinear Optical ◽

Nonlinear Optical Properties ◽

Time Dependent ◽

Hartree Fock ◽

Thiophene Derivatives

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Ab initio finite oligomer method for nonlinear optical properties of conjugated polymers. Hartree–Fock static longitudinal hyperpolarizability of polyacetylene

The Journal of Chemical Physics ◽

10.1063/1.469262 ◽

1995 ◽

Vol 102 (13) ◽

pp. 5350-5356 ◽

Cited By ~ 88

Author(s):

Bernard Kirtman ◽

Joseph L. Toto ◽

Kathleen A. Robins ◽

Muhammad Hasan

Keyword(s):

Optical Properties ◽

Conjugated Polymers ◽

Ab Initio ◽

Nonlinear Optical ◽

Nonlinear Optical Properties ◽

Hartree Fock

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Calculations of Perovskite Surface Relaxation

MRS Proceedings ◽

10.1557/proc-654-aa5.3.1 ◽

2000 ◽

Vol 654 ◽

Author(s):

E. Heifets ◽

E.A. Kotominc ◽

R.I. Eglitisc ◽

R.E. Cohen

Keyword(s):

Thin Films ◽

Surface Energy ◽

Ab Initio ◽

Shell Model ◽

Electron Correlation ◽

Surface Relaxation ◽

Hartree Fock ◽

Semi Empirical ◽

Good Agreement ◽

Correlation Corrections

AbstractThe (100) and (110) surface relaxations are calculated for SrTiO3 and BaTiO3 perovskite thin films by means of a semi-empirical shell model (SM) for different surface terminations. Our SM results for the (100) surface structure are in good agreement with our present ab initio Hartree-Fock calculations with electron correlation corrections, previous ab initio pseudopotential calculationsand LEED experiments. The surface energy for the Ba-, Sr-, TiO- terminated (110) surfaces is found much larger than that for the (100) one. In contrast, the surface energy for the asymmetric O-termination, where outermost O atoms are strongly on-plane displaced, is the lowest for all (110) terminations and thus the most stable.

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A semi-empirical estimation of ground and excited state dipole moments of zinc phthalocyanine from solvatochromic shift data

International Journal of Advanced Chemistry ◽

10.14419/ijac.v6i2.11019 ◽

2018 ◽

Vol 6 (2) ◽

pp. 190

Author(s):

Abimbola Ogunsipe

Keyword(s):

Excited State ◽

Ground State ◽

Dipole Moments ◽

Solvent Polarity ◽

Zinc Phthalocyanine ◽

Empirical Estimation ◽

Solvatochromic Shift ◽

Excited State Dipole Moments ◽

Semi Empirical ◽

Ground State Dipole Moments

A semi-empirical determination of ground and excited state dipole moments of zinc phthalocyanine (ZnPc) from solvatochromic shifts is hereby presented. The ratio of the excited- and ground-state dipole moments of ZnPc ( ) was estimated by a combination of the Bakshiev and the Kawski-Chamma-Viallet’s equations, while the difference in the excited- and ground-state dipole moments (Dm) was estimated usingthe molecular-microscopic solvent polarity parameters ( ), alongside the Stokes’ shifts (Dῡ) in the various solvents. The dipole moment of ZnPc is significantly higher in the excited singlet state (me = 3.12 D) than in the ground state (mg = 1.50 D). Obviously charge separation is greater in the excited state of ZnPc than in its ground state.

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CO isotopologue ratios in the solar photosphere

Proceedings of the International Astronomical Union ◽

10.1017/s1743921316003124 ◽

2015 ◽

Vol 11 (A29A) ◽

pp. 307-308

Author(s):

James R. Lyons ◽

Ehsan Gharib-Nezhad ◽

Thomas R. Ayres

Keyword(s):

Dipole Moment ◽

Ab Initio ◽

Dipole Moments ◽

Isotope Ratios ◽

Moment Function ◽

Solar Photosphere ◽

Ab Initio Methods ◽

Infrared Observations ◽

Semi Empirical

AbstractWe re-evaluate the CO dipole moment function in order to obtain more accurate isotope ratios for the solar photosphere using previous infrared observations. We used a new set of dipole moments from HITEMP which were accurately determined by both semi-empirical and ab initio methods. Preliminary values of isotope ratios using the new dipole moments are in better agreement with the inferred photosphere values from Genesis, showing that the solar photosphere is isotopically similar to primitive inclusions in meteorites.

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