Choosing the polarization of the laser,changing the wavelength of the excitation laser and the strength of an external electric field synchronously to keep scal edenergy constant,we have measured M=0 constant scaledenergy absorption spectra of barium Rydberg atoms at scaledenergy ε=-300.Fourier transfor med recurrence spectra were compared with the closedorbit calculation for hydr ogen atom in the uniform approximation.The positions of experimental recurrence peaks fit well the theoretical ones,but the peak strengths differ remarkably,esp ecially in the region of scaledaction larger than 5.This may indicate a large effect of the barium core and the electron correlation on the electron dynamics.