Exact Solution of the PPP Model for Correlated Electronic States of Tetracene and Substituted Tetracene

Pati, Anusooya Y and Ramasesha, S (2014) Exact Solution of the PPP Model for Correlated Electronic States of Tetracene and Substituted Tetracene. In: JOURNAL OF PHYSICAL CHEMISTRY A, 118 (23). pp. 4048-4055.

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Abstract

Tetracene is an important conjugated molecule for device applications. We have used the diagrammatic valence bond method to obtain the desired states, in a Hilbert space of about 450 million singlets and 902 million triplets. We have also studied the donor/acceptor (D/A)-substituted tetracenes with D and A groups placed symmetrically about the long axis of the molecule. In these cases, by exploiting a new symmetry, which is a combination of C-2 symmetry and electron-hole symmetry, we are able to obtain their low-lying states. In the case of substituted tetracene, we find that optically allowed one-photon excitation gaps reduce with increasing D/A strength, while the lowest singlet triplet gap is only wealdy affected. In all the systems we have studied, the excited singlet state, S-i, is at more than twice the energy of the lowest triplet state and the second triplet is very close to the S-1 state. Thus, donor-acceptor-substituted tetracene could be a good candidate in photovoltaic device application as it satisfies energy criteria for singlet fission. We have also obtained the model exact second harmonic generation (SHG) coefficients using the correction vector method, and we find that the SHG responses increase with the increase in D/A strength.

Item Type:	Journal Article
Publication:	JOURNAL OF PHYSICAL CHEMISTRY A
Publisher:	AMER CHEMICAL SOC
Additional Information:	Copyright for this article belongs to the AMER CHEMICAL SOC, 1155 16TH ST, NW, WASHINGTON, DC 20036 USA
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited:	23 Jul 2014 10:34
Last Modified:	23 Jul 2014 10:34
URI:	http://eprints.iisc.ac.in/id/eprint/49511

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