Ab initio studies of the dipole polarizabilities of conjugated molecules Part 4. The dipole polarizability and first hyperpolarizability of o-benzyne and related molecules

1994 ◽  
Vol 313 (2) ◽  
pp. 265-273 ◽  
Author(s):  
Alan Hinchliffe ◽  
Humberto J. Soscún Machado
Keyword(s):  
Ab Initio ◽  
Dipole Polarizability ◽  
First Hyperpolarizability ◽  
Conjugated Molecules ◽  
Dipole Polarizabilities

Ab initio Hartree-Fock Investigation of π-Conjugated Compounds Presenting Large βv/βe Ratio: Merocyanines

1998 ◽  
Vol 63 (9) ◽  
pp. 1295-1308 ◽  
Author(s):  
Benoît Champagne ◽  
Thierry Legrand ◽  
Eric A. Perpete ◽  
Olivier Quinet ◽  
Jean-Marie André
Keyword(s):  
Ab Initio ◽  
First Hyperpolarizability ◽  
Conjugated Molecules ◽  
Hartree Fock ◽  
Experimental Discovery ◽  
Conjugated Compounds ◽  
Molecular Frame

CHF/6-311G* calculations of the first electronic and vibrational hyperpolarizabilities reveal that merocyanines present a substantial βv/βe ratio under their quinonoid nonpolar form. It originates from a large vibrational first hyperpolarizability whereas its electronic counterpart is small for this class of push-pull π-conjugated molecules. The transition from the quinonoid to the aromatic configuration is accompanied by an increase of βe and a decrease of the βv/βe ratio as well as by a ≈ 180° rotation in the plane of the molecule of βe and βv with respect to the molecular frame. Our results support the recent experimental discovery that antiparallel aggregation of aromatic and quinonoid forms of merocyanine is energetically favoured and that their first hyperpolarizabilities, which combine constructively, present both electronic and non purely electronic origins.

scholarly journals Density functional studies of the dipole polarizabilities of the linear polyacenes benzene through nonacene

2005 ◽  
Vol 3 (2) ◽  
pp. 361-369 ◽  
Author(s):  
Alan Hinchliffe ◽  
Beatrice Nikolaidi ◽  
Humberto Soscún Machado
Keyword(s):  
Ab Initio ◽  
Density Functional ◽  
Correlation Coefficients ◽  
Statistical Correlation ◽  
Tensor Component ◽  
Dipole Polarizability ◽  
Functional Studies ◽  
Absolute Agreement ◽  
Different Levels ◽  
Dipole Polarizabilities

AbstractWe report Ab Initio studies of the electric dipole polarizability of the linear polyacene series benzene through nonacene. A number of Ab Initio studies were done at different levels of theory for benzene, with all remaining Ab Initio calculations being at the B3LYP/6-311G(2d, 1p)//B3LYP/6-311+G(2d, 1p) level of theory. We find that the NN tensor component shows a constant increment of 20 atomic units per ring. AM1 and QSAR-quality empirical calculations show poor absolute agreement with the Ab Initio results but given excellent statistical correlation coefficients with the Ab Initio values. This implies that the results of such cheaper calculations can be suitably scaled for predictive purposes.

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