Inelastic collisions of fast charged particles with atoms: Bethe asymptotic formulas and shell corrections

Low-temperature inelastic collisions between hydrogen molecules and helium atoms.

Inelastic H(2):He collisions are studied from the experimental and theoretical points of view between 22 and 180 K. State-to-state cross sections and rates are calculated at the converged close-coupling level employing recent potential energy surfaces (PES): The MR-PES [J. Chem. Phys. 100, 4336 (1994)], and the MMR-PES and BMP-PESs [J. Chem. Phys. 119, 3187 (2003)]. The fundamental rates k(2-->...

An approximate analytical solution of the Bethe equation for charged particles in the range of radiotherapy energy

Charged particles such as protons and carbon ions are an increasing tool in radiation therapy. However, unresolved physical problems prevent optimal performance, including estimating the deposited dose in non-homogeneous tissue, is an essential aspect of optimizing treatment. The Monte Carlo (MC) method can be used to estimate the amount of radiation, but, this powerful computing operation is v...

Spin-exchange collisions of submerged shell atoms below 1 Kelvin.

Angular momentum changing collisions can be suppressed in atoms whose valence electrons are submerged beneath filled shells of higher principle quantum number. To determine whether spin-exchange collisions are suppressed in these "submerged shell" atoms, we measured collisional rates for six hyperfine states of Mn at T < 1 K. Although the 3d valence electrons in Mn are submerged beneath a fille...

Spin - Exchange Collisions of Submerged Shell Atoms Below

Thermalization of fast cesium 5D3/2 atoms in collisions with ground-state cesium atoms

We have investigated collisions involving fast, excited Cs atoms produced by photodissociating Cs2 molecules with a pulsed dye laser. The velocities of the atoms in the 5D state formed by the process Cs2sX Sg d+"vpump→Cs2→Css5Dd+Css6Sd are much greater than typical thermal velocities associated with the cell temperature. Using a narrow-band cw probe laser to observe the increased Doppler broade...