Influences of microscopic parameters of chiral molecules on the zero-frequency first hyperpolarizabilities

Based on one-electron-on-a-helix model and two-coupled-oscillator model, zero-frequency first hyperpolarizabilities of chiral molecules are investigated. Their expressions and the relations between them and microscopic parameters of chiral molecules are obtained by theoretical derivation. Furthermore, the relations of zero-frequency first hyperpolarizabilities with the wavelength of incident light and microscopic parameters of chiral molecules are simulated numerically. We find the fact that influences of microscopic parameters of chiral molecules on zero-frequency first hyperpolarizabilities are different by using different chiral molecular microscopic parameters such as the helix radius and the helix pitch for one-electron-on-a-helix model and α for two-coupled-oscillator model. Furthermore, the influence of microscopic molecular parameter to the zero-frequency first hyperpolarizabilities can also help to comprehend nonlinear optical mechanism of chiral molecules.