Theoretical study of the structures and nonlinear optical properties of hydrogen-bonded nitroaniline systems

The structures, first-, second-, and third-order polarizabilities for the linear hydrogen-bonded p-nitroaniline systems 1a–5a and related systems 2b–5b are calculated by the use of ab initio and PM3 semiempirical methods. The difference of ab intio and PM3 calculated OH hydrogen bond distances between NO2 and NH2 groups for 2a, 3a, 2b, and 3b are 0.31, 0.31, 0.18, and 0.27, respectively. The PM3-predicted frequency dependent asymptotic values of γ for the frequencies of 0.0eV, 0.25eV, and 0.5eV are 5.3e5, 5.7e5, and 7.4e5 10−36 esu in the linear types, respectively. The linear hydrogen bonded p-nitroaniline systems exhibit power law dependences with the exponents 1.5852, 1.5946, and 1.6272, repectively.