IMPURITY ANOMALY OF HEAT-CAPACITY IN SOLID PARAHYDROGEN AND ORTHODEUTERIUM

The heat capacity of solid solutions of neon in hydrogens with central intermolecular interaction (p-H-2 and o-D-2) is studied in the 0.8-8K temperature range. Temperature dependence of the neon impurities cont ribution (at concentrations x less than or equal to 0.25 mol. %) to he at capacity of such solutions passes its maximum at T=5.8 K. The magni tude of the effect does not depend on concentration of J=1 modificatio ns of hydrogens (o-H-2 and p-D-2) and thus is determined by central in termolecular interaction only. In the case of solutions of Ne in p-H-2 , the impurity contribution per neon atom exceeds 9k(B). An assumption is discussed that the very large impurity effects are due to the chan ge of the location of hydrogen and deuterium molecules near heavy neon atoms at the temperature change.