Approaching the classical limit in the diamagnetic helium atom

Abstract

We studied the diamagnetic helium atom under conditions of constant scaled energy over an extended range of Rydberg levels (nϭ77Ϫ160). Experimental spectra are compared with extensive quantum calculations. In the studied range the effective Planck constant ប e varies a factor of 2 ͑from 0.01 to 0.005͒. When comparing Fourier-transformed spectra in different ប e regimes, the resulting action spectra show a large similarity, in accordance with the invariance of the classical dynamics. Prominent variations in the recurrence strength of peaks in the action spectra with ប e could be attributed to interferences between orbits with nearly the same scaled action. In particular, the predicted difference in ប e scaling of the orbit parallel to the magnetic field when compared with the off-axis orbits is confirmed experimentally. ͓S1050-2947͑99͒00509-0͔

Contribution of forbidden orbits in the photoabsorption spectra of atoms and molecules in a magnetic field

“…The rôle of the perpendicular on-node orbit was first observed in calculations for the diamagnetic hydrogen atom at low scaled energy (ǫ ≃ −0.7) [7]. Subsequent high-resolution experiments on helium in a magnetic field in the same dynamical regime did not clearly detect the on-node orbits (they were within the experimental noise) [14]. We have given a simpler derivation of the contribution of these first-order suppressed orbits, and our numerical results indicate that on-node orbits are more likely to be detected in non-hydrogenic atomic or molecular systems with strong quantum defects.…”

Semiconductor hydrogen analogue candidates for observation of quasi‐Landau oscillations associated with semi‐classical electron orbits

“…In addition to the preceding numerical results, we emphasize the point that the experimental method proposed in , and utilized in, , may improve the resolution of these electron orbit periods. This is a method called Constant Scaled Energy Spectroscopy, which involves adjusting the magnetic field and incident frequency on the sample to hold constant.…”