ZINDO, nonlinear optics calculations

ZINDO57-58 is a semiempirical intermediate neglect of differential overlap/spectroscopy (INDO/S) based routine. It can be combined with an SOS method to calculate second-order nonlinear optical coefficients. ZINDO is parametrized to accommodate transition-metal calculations and is therefore suited for calculation on organometallic compounds. To achieve computational efficiency, some of the terms in Eq. (2) are replaced by empirical data or neglected. To see how the INDO/S does this, the closed-shell case will be examined.57 58 It is useful to introduce the following ... 

Semi-empirical ZINDO SOS (sum over states) and ab initio quadratic response function (DDRPA) calculations on a series of D-A-substituted 7t-conjugated chromophores based on styryl benzothiazoles were used to aid in the design of dyes with high nonlinear optical properties <2004PCP495>. 

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