Kubo (1962) predicted that heat capacity of a metal nanoparticle should show an exponential behavior at 1 K or below. However, no such report is seemingly available in literature until date, except its negative or enhanced values. If one sample or the other of a metal nanoparticle (say, cobalt) sample show both exponential form and discrete jumps that too between 15 K to 45 K, how should it be justified?