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Iodine‐doped transpolyacetylene
Author(s) -
Das G. P.,
Yeates A. T.,
Dudis D. S.
Publication year - 1996
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/(sici)1097-461x(1996)60:7<1499::aid-qua31>3.0.co;2-x
Subject(s) - excited state , chemistry , polyene , homo/lumo , ab initio , ground state , atomic physics , atom (system on chip) , charge (physics) , molecular physics , physics , molecule , quantum mechanics , organic chemistry , computer science , embedded system
With a view to elucidate and develop a model for the mechanism of conduction in doped transpolyacetylene (t‐PA), we have carried out an ab initio study of the ground and excited state of transoctatetraene in the presence of an iodine atom. While the ground state is calculated as characterized by a slightly distorted alternating bond geometry, with iodine remaining largely neutral on top of the plane of the polyene near roughly the midpoint of the chain axis, the excited state has the geometry characterized by a solitonic distortion with the octatetraene carrying a net positive charge close to 0.7e. The bandgap [highest occupied to lowest unoccupied molecular orbital (HOMO(SINGLEBOND)LUMO) gap] is computed to be nearly 0.8 eV. Moreover, the excited‐state energy appears very insensitive to the position of iodine along the axis of the octatetraene chain. As an extension of an earlier calculation on the transport of charge by a charged soliton, a similar calculation is performed on a C 8 H 10 + “kink” traveling along the backbone of C 12 H 14 + , yielding very similar results. A computer code has been developed to compute the transport velocity of charge based on the above model and can be used in conjunction with the GAMESS program package. © 1996 John Wiley & Sons, Inc.