The ground states of Lennard-Jones clusters (LJ(n)) for sizes tip to n = 147 are estimated as a function of the de Boer quantum delocalization length, Lambda, using the variational Gaussian wavepacket method. Consequently, the n-Lambda phase diagram is constructed showing the ranges of stability of various structural motifs, including the Mackay and anti-Mackay icosahedra, several nonicosahedral but highly symmetric structures, and liquidlike (or disordered) structures. The increase in Lambda favors more disordered and diffuse structures over more symmetric and compact ones, eventually making the liquidlike structures most energetically favorable.