In This paper some problems, which should be noticed in the measurements of organicmolecular first hyperpolarizability（β） by the solvatochromism , are discussed based on the resultsof the measurements for 11 compou...In This paper some problems, which should be noticed in the measurements of organicmolecular first hyperpolarizability（β） by the solvatochromism , are discussed based on the resultsof the measurements for 11 compounds .The experiments indicate theat the selection of solvent used is the basis of the method to fit for use. The determination of the parameter a, which is the radius of a spherical cavity occupied by the molecules in the solutions, is the key to decide’the reasonableness of the obtained results and the formula for a=1/2(l’+rv),has been suggestedin which l is the molecular length of the nonlinear optical active part and can be obtained fromvalues of bond lengths in literature, rv is the average spherical radius of used solvents.展开更多
The nonlinear optical properties of title compounds calculated by AM1/finite field (AM1/FF) approach are discussed based on their crystal parameters. The origins of large molecular first hyperpolarizabilities β and g...The nonlinear optical properties of title compounds calculated by AM1/finite field (AM1/FF) approach are discussed based on their crystal parameters. The origins of large molecular first hyperpolarizabilities β and good transparency of the compounds are explained well through the aromatic character enhancement in the excited state and the short conjugation length in the ground state. Results show that the difference of β values obtained by two experimental methods (Solvatochromic and Hyper Rayleigh Scattering) is due to the molecular quasi two dimension character and the octupolar components’ contribution. The calculation has also demonstrated that the change of β xxx caused by different donor substituents is linearly related with the Hammett substituent constant σ +.展开更多
文摘In This paper some problems, which should be noticed in the measurements of organicmolecular first hyperpolarizability（β） by the solvatochromism , are discussed based on the resultsof the measurements for 11 compounds .The experiments indicate theat the selection of solvent used is the basis of the method to fit for use. The determination of the parameter a, which is the radius of a spherical cavity occupied by the molecules in the solutions, is the key to decide’the reasonableness of the obtained results and the formula for a=1/2(l’+rv),has been suggestedin which l is the molecular length of the nonlinear optical active part and can be obtained fromvalues of bond lengths in literature, rv is the average spherical radius of used solvents.
文摘The nonlinear optical properties of title compounds calculated by AM1/finite field (AM1/FF) approach are discussed based on their crystal parameters. The origins of large molecular first hyperpolarizabilities β and good transparency of the compounds are explained well through the aromatic character enhancement in the excited state and the short conjugation length in the ground state. Results show that the difference of β values obtained by two experimental methods (Solvatochromic and Hyper Rayleigh Scattering) is due to the molecular quasi two dimension character and the octupolar components’ contribution. The calculation has also demonstrated that the change of β xxx caused by different donor substituents is linearly related with the Hammett substituent constant σ +.
