Variational Estimation of the Wave Function at Origin for Heavy   Quarkonium
  The wave function at the origin (WFO) is an important quantity in studying many physical problems concerning heavy quarkonia. However, when one used the variational method with fewer parameters, in general, the deviation of resultant WFO from the "accurate" solution was not well estimated. In this paper, we discuss this issue by employing several potential forms and trial wave functions in detail and study the relation between WFO and the reduced mass. 
Yi-Bing Ding, Xue-Qian Li, Peng-Nian Shen