Abstract:

The polarizabilities, first and second hyperpolarizabilities of urea, urea dimer and trimer have been studied by ab initio/couple perturbed Hartree-Fork (CPHF) method. A polyurea molecule contains two or more alternatively ordered electron-donating and electron-withdrawing groups. Compared to urea, its dimer and trimer possess much greater nonlinear optical susceptibilities. The calculations also show a particularly intramolecular short-range, rather than long-range, charge transfer.

Key words: Ab initio, Urea, Polyurea, Nonlinear optical property, Dipole moment