4 research outputs found
The evidence of quasi-free positronium state in GiPS-AMOC spectra of glycerol
We present the results of processing of Age-Momentum Correlation (AMOC)
spectra that were measured for glycerol by the Gamma-induced positron
spectroscopy (GiPS) facility. Our research has shown that the shape of
experimental s(t) curve cannot be explained without introduction of the
intermediate state of positronium (Ps), called quasi-free Ps. This state yields
the wide Doppler line near zero lifetimes. We discuss the possible properties
of this intermediate Ps state from the viewpoint of developed model. The amount
of annihilation events produced by quasi-free Ps is estimated to be less than
5% of total annihilations. In the proposed model, quasi-free Ps serves as a
precursor for trapped Ps of para- and ortho-states
Formation of quasi-free and bubble positronium states in water and aqueous solutions
It is shown that in aqueous solutions a positronium atom is first formed in
the quasi-free state, and, after 50-100 ps, becomes localized in a nanobubble.
Analysis of the annihilation spectra of NaNO3 aqueous solutions shows that the
hydrated electron is not involved in the positronium (Ps) formation
Formation of Quasi-Free and Bubble Positronium States in Water and Aqueous Solutions
It is shown that in aqueous solutions a positronium atom is first formed in the quasi-free state, and, after 50-100 ps, becomes localized in a nanobubble. Analysis of the annihilation spectra of aqueous solutions shows that the hydrated electron is not involved in the positronium (Ps) formation
Positrons and Positronium Atoms in a Condensed Phase Close to Its Melting Point
Investigation of the local heating effect at the terminal part of a fast positron track sheds light on the accumulation of defects in a frozen medium close to its melting point. Estimations of the formation energies of the structural defects which may trap the Ps atom as well as a contribution of these defects to the enthalpy of fusion are obtained