Theory of molecular optoelectronics: calculations for DAN

Molecular materials can have high nonlinear optical response with good resistance to laser damage. The authors have developed a theory relating molecular crystal nonlinear susceptibilities to the molecular hyperpolarizabilities. Semi-empirical calculations of the first hyperpolarizability tensor β suffice to predict the quadratic susceptibility tensor χ⁽²⁾ reasonably well for the few crystals where all requisite input data are available. They now apply the same method to the title compound DAN, 4-(N,N-dimethylamino)-2-acetamido-nitrobenzene. This is of interest because it has a particularly high χ⁽²⁾ and is used in crystal-cored fibres. However, the noncentrosymmetric structure necessary for nonzero χ⁽²⁾ is facilitated by hydrogen bonding of the acetamido groups; since this is not incorporated in the β calculations, they may be less reliable for predicting χ⁽²⁾ in this case