Ultra-low energy integral scattering cross-sections in helium and the helium dimer binding energy

There has been considerable recent interest in low-temperature interrogation of quantum helium nanodroplets. We consider the interaction of helium ground and metastable states, employing the best known molecular dimer potentials. Radiative transitions between different metastable rovibrational levels are compared with the discharge emission transition lines and good agreement is found. Collisional interactions between helium ground and metastable atoms are studied and elastic scattering, metastability excitation transfer and diffusion cross sections and rate coefficients are calculated at ultralow energies. The integral elastic cross section at ultralow energies is about $5000 {\mathrm{\AA{}}}^{2}.$ Effect of shape resonances that form in the potential barriers, on the cross sections is investigated. We find that some shape resonances live for longer than 100 s. Long-range potential wells could support ``shelf'' levels. We discuss their collisional and spectroscopic properties.There has been considerable recent interest in low-temperature interrogation of quantum helium nanodroplets. We consider the interaction of helium ground and metastable states, employing the best known molecular dimer potentials. Radiative transitions between different metastable rovibrational levels are compared with the discharge emission transition lines and good agreement is found. Collisional interactions between helium ground and metastable atoms are studied and elastic scattering, metastability excitation transfer and diffusion cross sections and rate coefficients are calculated at ultralow energies. The integral elastic cross section at ultralow energies is about $5000 {\mathrm{\AA{}}}^{2}.$ Effect of shape resonances that form in the potential barriers, on the cross sections is investigated. We find that some shape resonances live for longer than 100 s. Long-range potential wells could support ``shelf'' levels. We discuss their collisional and spectroscopic properties.

Physical Review AJun 13, 200210 citations

Low temperature scattering of helium and hydrogen

John C. Mester, Eric Meyer, T. E. Huber +2 more

Physica B Condensed MatterFeb 1, 19943 citations

Differential cross sections for elastic scattering of metastable helium from helium and argon

Joachim Großer, Hellmut Haberland

Physics Letters ASep 1, 196810 citations

“Eclipse” Effect in the Scattering of Weakly Bound Helium Clusters

Anton Kalinin, Oleg Kornilov, Lev Yu. Rusin +2 more

The total cross sections of the helium dimer, trimer, and tetramer for scattering from Kr atoms have been measured for cluster beam velocities between 250 and 820 m/s. The dimer cross section is twice that of the atom within 5% indicating that the Kr atoms scatter from the He atoms independently, which is consistent with the large dimer bond distance of about 50 A. The trimer and tetramer cross sections are somewhat larger and can be described by an impulse approximation with a multiple "eclipse" correction, extending ideas of Glauber for high energy collisions with the deuteron.The total cross sections of the helium dimer, trimer, and tetramer for scattering from Kr atoms have been measured for cluster beam velocities between 250 and 820 m/s. The dimer cross section is twice that of the atom within 5% indicating that the Kr atoms scatter from the He atoms independently, which is consistent with the large dimer bond distance of about 50 A. The trimer and tetramer cross sections are somewhat larger and can be described by an impulse approximation with a multiple "eclipse" correction, extending ideas of Glauber for high energy collisions with the deuteron.

Physical Review LettersOct 13, 20049 citations

Ultra-low energy elastic scattering in a system of three He atoms

Vladimir Roudnev

arXiv:physics/0206058Chemical Physics LettersJan 1, 200342 citations

5000 {\mathrm{\AA{}}}^{2}.

Effect of shape resonances that form in the potential barriers, on the cross sections is investigated. We find that some shape resonances live for longer than 100 s. Long-range potential wells could support ``shelf'' levels. We discuss their collisional and spectroscopic properties.