Positronium in Phase IV and Rotator Phase of Long-Chain Alkanes

B. Zgardzińska and T. Goworek Lublin Positron Group (UMCS), pl. Marii Curie-Skłodowskiej 1, 20-031 Lublin, Poland

Full Text PDF

Received: 3 09 2007;

Ortho-positronium lifetime and intensity was measured as a function of temperature and pressure for some n-alkanes in which so-called "phase IV" appears. This phase is characterized by slightly increased ortho-positronium lifetime compared to low-temperature phases. It was found that the effect of quenching positronium by light does not appear in all phases from phase IV upwards. The lifetime in the rotator phases becomes equal to that in liquids, and only the change of positronium formation intensity allows to detect the solid-liquid transition in positron lifetime measurements.

DOI: 10.12693/APhysPolA.113.1551 PACS numbers: 36.10.Dr, 61.80.Fe, 71.60.+z, 78.70.Bj