The first observation to our knowledge of a second-order nonlinear optical effect in a nonpolar molecular ion is reported. Hyper-Rayleigh scattering was observed from aqueous and organic solutions of the tricyanomethanide ion [C(CN)3]−. Because of the absence of a dipole moment and the presence of a charge in this planar, nonpolar, but highly polarizable molecular anion with D3h symmetry, no electric-field-induced second-harmonic-generation experiments are possible. The experimental values for the first hyperpolarizability βxxx [(7 ± 1.5) × 10−30 esu, independent of the solvent] are in good agreement with the results from quantum-chemical calculations.
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics