Abstract: The strontium atoms in ground states were excited to higher |M|=1 Rydberg states while the laser wavelength and the electric field strength are scanned simultaneously to keep the scaled-energy ε constant. Spectra were recorded for ε=-3.00, -2.50 and -1.88. The experimental Fourier transform recurrence spectra were compared with the hydrogenic closed-orbit calculation. The positions of the experimental recurrence peaks were well coincided with the theory, but the strengths of the peaks were strongly affected by the strontium core effect.

Keywords: 
• strontium atom /
• scaled-energy spectroscopy /
• closed-orbit theory