On using Fourier series and Legendre polynomials as angular basis sets for nonrotating triatomic molecules

The numerical properties of quantum grid methods applying the Fourier series and Legendre polynomials as angular basis sets for triatomic molecule calculations are compared. The three-dimensional time-dependent wavepacket calculations (J = 0) by using relaxation technique are performed to obtain the lowest vibrational eigenvalues of ground electronic states of OBrO and van der Waals Na⋯FH molecules. For the OBrO molecule with a deep well potential along bending mode, the numerical models using the Fourier series with fast Fourier transform technique as the angular basis set are very efficient. And the Legendre polynomials is appropriate to describe the Na⋯FH molecule with a floppy potential along bending mode.