Thermal corrections of lowest order for a helium atom

CORRECTIONS OF ORDER αm TO S-LEVELS OF HELIUM

Several new corrections of ordermα to the energy levels of S states in helium are obtained from radiative corrections to the Breit potential and from the polarization insertions in the two photon exchange graphs. While individual gauge invariant contributions are comparable to current experimental errors, the sum of these corrections is an order of magnitude smaller due to mutual cancellations....

Higher-order Stark effect on an excited helium atom

Degenerate perturbation theory is used to study dipole susceptibilities of an excited helium atom in an external electric field. The dependence of the perturbed energy of levels in atoms on fine-structure effects and on the higher-order Stark effect is investigated. Numerical results have been obtained for the (1s3p) P0 and (1s3p) P2 states of helium. The magnitude of the electric field and the...

Semiclassical theory of helium atom

Scattering Length for Helium Atom-Diatom Collision

We present results on the scattering lengths of He–He2 and He–He2 collisions. We also study the consequence of varying the coupling constant of the atom-atom interaction.

Searching for dark matter with helium atom

With the help of the boost operator we can model the interaction between a weakly interacting particle(WIMP) of dark matter(DAMA) and an atomic nuclei. Via this “kick” we calculate the total electronic excitation cross section of the helium atom. The bound spectrum of He is calculated through a diagonalization process with a configuration interaction (CI) wavefunction built up from Slater orbit...