Comparative study of the molecular structure of stilbene using molecular mechanics, Hartree–Fock and density functional theories

Claes, Luc; Kwasniewski, Sergiusz; Deleuze, Michaël S.; François, J

doi:10.1016/s0166-1280(01)00496-1

Cited by 19 publications

(12 citation statements)

References 30 publications

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“…Similarly distorted dihedral angle of 26.7 • for stilbene molecule (PPV1) was also obtained with the MP2/6-31G** method. 10 This is in agreement with the electron diffraction experiment where the nonplanar stilbene structure (31 • ±5 • ) 11 was described. In contrast, the density functional theory (DFT) 12 in several basis sets and semiempirical parametric method 3 (PM3) 13 calculations favor the nearly or totally planar structures.…”

Section: Introductionsupporting

confidence: 89%

TORSIONAL POTENTIALS AND FULL-DIMENSIONAL SIMULATION OF ELECTRONIC ABSORPTION SPECTRA OF para-PHENYLENEVINYLENE OLIGOMERS USING SEMIEMPIRICAL HAMILTONIANS

Lukeš

Šolc

Barbatti

et al. 2010

J. Theor. Comput. Chem.

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A systematic study of torsional potential curves in electronic ground state based on second-order Møller-Plesset energy (MP2), density functional theory (DFT), and Austin mode 1 (AM1) methods is presented for para-phenylenevinylene oligomers constructed from two to four aromatic rings. The semiempirical AM1 approach gives the correct location of potential energy minima in comparison with the reference MP2 calculations and literature data. However, the semiempirical AM1 energy barriers at perpendicular orientation are ca. 30% smaller than the MP2 ones. The DFT calculations indicate optimal planar structures and the barriers are three times higher than MP2 values. Excited-state potential energy curves evaluated from vertical excitations at the time-dependent density functional theory (TD-DFT) and ab initio CI levels exhibit much steeper increase of values in the vicinity of perpendicular orientation than in the semiempirical Zerner's intermediate neglect of differential overlap (ZINDO) and ab initio RI-CC2 cases. The effects of vibrational motion of phenylene rings on the torsional broadening of absorption spectra were estimated from semi-classical molecular dynamics simulations and harmonic oscillator sampling. The simulated spectra agree well with the experiment and allow estimating the conformer distribution of the molecules. Keywords: PPV; stilbene; potential energy surface; ab initio; RI-CC2. ¶ Corresponding authors. 249 J. Theor. Comput. Chem. 2010.09:249-263. Downloaded from www.worldscientific.com by FUDAN UNIVERSITY on 05/16/15. For personal use only. 250 V. Lukeš et al.

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Section: Introductionsupporting

confidence: 89%

TORSIONAL POTENTIALS AND FULL-DIMENSIONAL SIMULATION OF ELECTRONIC ABSORPTION SPECTRA OF para-PHENYLENEVINYLENE OLIGOMERS USING SEMIEMPIRICAL HAMILTONIANS

Lukeš

Šolc

Barbatti

et al. 2010

J. Theor. Comput. Chem.

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“…Noticeable discrepancies, up to 15°, are observed between the MP2 (Table 1) and the DFT (Tables 2 and 3) transition states for the C β ‐C α ‐S α ‐C 1 , C α ‐S α ‐C 1 ‐S 1 , and C 1 ‐S 1 ‐C β ‐C α dihedral angles. Again, in straightforward analogy with recent studies of the ground‐state structure of trans ‐stilbene,33, 34 it appears that the DFT/B3LYP and MPW1K methods more strongly drive the transition state toward planarity compared with the MP2 level. In comparison with the MP2 level, the DFT(MPW1K) and DFT(B3LYP) methods also provide systematically a significantly longer C α S α bond (by ≈0.1 and ≈0.2 Å, respectively) and shorter C β H β bond (by ≈0.03 and ≈0.04 Å, respectively) in the transition state.…”

Section: Assessment Of the Theoretical Methodssupporting

confidence: 62%

Theoretical study of the internal elimination reactions of xanthate precursors

2003

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The gas-phase internal elimination (E(i)) reaction of ethyl xanthate (CH(3)-CH(2)-S-CS-O-CH(3)) has been investigated by means of Hartree-Fock, second-order Møller-Plesset, and density functional theory (DFT) using the Becke three-parameter Lee-Yang-Parr (B3LYP) functional and the modified Perdew-Wang one-parameter model for kinetics (MPW1K). Considerable differences between the ground- and transition-state geometries and the calculated activation energies are observed from one approach to the other, which justifies first a careful calibration of the methods against the results of benchmark CCSD(T) calculations. Compared with these, DFT calculations along with the MPW1K functional are found to be an appropriate choice for describing the E(i) reaction of xanthate precursors. The precursor conformation and the transition states involved in the internal conversion of xanthate precursors of cyano derivatives of ethylene, and of cis- and trans-stilbene, are then characterized in detail by means of this functional.

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“…The MD computations have been performed using the 3.1 version of the TINKER package of programs 57 together with the MM3(92) force field 47–49. This force field has been preferred to a more recent MM3(96) version because in the particular case of tS the calculated geometries are slightly better when compared to the results of DFT 58–60 calculations 61 carried out with the B3LYP functional 62, 63 in conjunction with Dunning's cc‐pVDZ basis set 64, an approach which in turn compares favorably well with benchmark calculations at the CCSD(T) level 65–68. Compared also with elements of the B3LYP/cc‐pVD2 potential energy surface, such as the dependence of the total energy on the C 1 –C 2 –C 3 –C 4 dihedral angle about the C 2 –C 3 single bond (in short, ϕ, see Fig.…”

Section: Theory and Computational Detailsmentioning

confidence: 99%

Temperature effects on the UV–Vis electronic spectrum of trans‐stilbene

Kwasniewski¹,

François²,

Deleuze³

2001

Int J of Quantum Chemistry

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ABSTRACT:The ultraviolet (UV)-Visible absorption spectrum of trans-stilbene (tS) is computed at different temperatures by couplin g molecular dynamic s (MD ) simulations with the classical MM 3 force fiel d to ZINDO/S-CI S calculation s of vertical excitation energies and transition dipol e moments. The selection of a large number of structures along the MDtrajectories enables a consistent treatment of temperature effects in the vacuum , whereas the ZINDO/S-CI S calculation s permit a reliable treatment of electron correlation and relaxation, taking account of multistat e interactions in the fina l state. Thermal motions are found to alter very differentl ythe width and shape of bands. Structural alterations such as the stretching and the torsion of the vinyl single and double bonds very stronglyinfluenc e the appearance of the fi rst valence state, pertaining to the highest occupied and lowest unoccupied molecular orbital (HOMO-LUMO ) transition. At temperatures less than 400 K, these are found to yield a merelyGaussian and very pronounce d thermal broadenin g of the related band (A), up to nearly 30 nm, together with a minor blue shift of its maximum λ max . In contrast, a red shift by several nanometers occurs due to thermal motions for the remainin g three valence bands. As can be expected, the broadenin g intensifie s at higher temperatures, and for the A-band , becomes markedly asymmetric when T exceeds 400 K. The combinatio n of MD(MM3 ) and ZINDO/S-CIS computation s enables also consistent calculation s of hot bands, which are forbidden by symmetryat 0 K.

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Comparative study of the molecular structure of stilbene using molecular mechanics, Hartree–Fock and density functional theories

Cited by 19 publications

References 30 publications

TORSIONAL POTENTIALS AND FULL-DIMENSIONAL SIMULATION OF ELECTRONIC ABSORPTION SPECTRA OF para-PHENYLENEVINYLENE OLIGOMERS USING SEMIEMPIRICAL HAMILTONIANS

TORSIONAL POTENTIALS AND FULL-DIMENSIONAL SIMULATION OF ELECTRONIC ABSORPTION SPECTRA OF para-PHENYLENEVINYLENE OLIGOMERS USING SEMIEMPIRICAL HAMILTONIANS

Theoretical study of the internal elimination reactions of xanthate precursors

Temperature effects on the UV–Vis electronic spectrum of trans‐stilbene

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