Collision-Produced Atomic States

Abstract We study a new dark sector signature for an atomic process of “rearrangement” in the galaxy. In this process, a hydrogen-like atomic dark matter state together with its anti-particle can rearrange to form a highly-excited bound state. This bound state will then de-excite into the ground state emitting a large number of dark photons that can be measured in experiments on Earth through their kinetic mixing with the photon. We find that for DM masses in the GeV range, the dark photons have enough energy to pass the thresholds of neutrino observatories such as Borexino and Super-Kamiokande that can probe for our scenario even when our atomic states constitute a small fraction of the total DM abundance. We study the corresponding bounds on the parameters of our model from current data as well as the prospects for future detectors.

Download Full-text

Coulomb energy averaged over thenlN-atomic states with a definite spin

International Journal of Quantum Chemistry ◽

10.1002/qua.560530506 ◽

1995 ◽

Vol 53 (5) ◽

pp. 495-499 ◽

Cited By ~ 5

Author(s):

M. Kibler ◽

Yu. F. Smirnov

Keyword(s):

Coulomb Energy ◽

Atomic States

Download Full-text

A First-Principles Study of Hydrogen Desorption from High Entropy Alloy TiZrVMoNb Hydride Surface

Metals ◽

10.3390/met11040553 ◽

2021 ◽

Vol 11 (4) ◽

pp. 553

Author(s):

Jinjing Zhang ◽

Jutao Hu ◽

Haiyan Xiao ◽

Huahai Shen ◽

Lei Xie ◽

...

Keyword(s):

Density Functional ◽

Underlying Mechanism ◽

Hydrogen Desorption ◽

High Entropy Alloy ◽

Hydrogen Atoms ◽

Desorption Process ◽

High Entropy ◽

The Density Functional Theory ◽

Hydride Hydrogen ◽

Atomic States

The desorption behaviors of hydrogen from high entropy alloy TiZrVMoNb hydride surface have been investigated using the density functional theory. The (110) surface has been determined to be the most preferable surface for hydrogen desorption from TiZrVMoNb hydride. Due to the high lattice distortion and heterogeneous chemical environment in HEA hydride, hydrogen desorption from the HEA hydride surface is found to be complex. A comparison of molecular and atomic hydrogen desorption reveals that hydrogen prefers to desorb in atomic states from TiZrVMoNb hydride (110) surface rather than molecular states during the hydrogen desorption process. To combine as H2 molecules, the hydrogen atoms need to overcome attractive interaction from TiZrVMoNb hydride (110) surface. These results suggest that the hydrogen desorption on TiZrVMoNb hydride (110) surface is a chemical process. The presented results provide fundamental insights into the underlying mechanism for hydrogen desorption from HEA hydride surface and may open up more possibilities for designing HEAs with excellent hydrogen desorption ability.

Download Full-text