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Internet Electronic Journal of Molecular Design - IEJMD, ISSN 1538-6414, CODEN IEJMAT
| ABSTRACT - Internet Electron. J. Mol. Des. March 2005, Volume 4, Number 3, 226-234 |
Effect of Twist Angle on Calculated Second Order Non-Linear Responses of
Novel Charge Transfer Molecular Systems
B. A. Sriyanka Mendis and K. M. Nalin de Silva
Internet Electron. J. Mol. Des. 2005, 4, 226-234
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Abstract:
Molecules with large optical non-linearities have extensively
been studied due to their potential applications in the area of
materials science and various photonic technologies, including
optical switching and data processing. Semi-empirical quantum
chemical calculations are performed on the class of compounds
shown in Figure 1 which show very large non-linear optical
activity. The effect of twist angle (1234) on the static
hyperpolarizability was investigated. Geometries of all molecules
were optimized at the semi-empirical level of the theory using
AM1 Hamiltonian using MOPAC 6.0 computational package.
The static hyperpolarizabilities, β, and frontier molecular orbital
energies are studied as a function of the twist angle (1234),
between the diaminomethylene unit and the six membered fused
rings as shown in Figure 1 using AM1 Hamiltonian within
MOPAC 6.0 computational chemistry package. All the β values
that we report here are the magnitude of static
hyperpolarizability. The enormous enhancement of the
hyperpolarizability for a particular dihedral angle of these
designed novel molecular systems is also reported. The study
reveals that these classes of organic compounds show a very
large hyperpolarizability and hence in general may have potential
applications in the development of non-linear optical materials.
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