In this work,we propose two modifications to the well-known basin hopping(BH)optimization algorithm [D.J.Wales and J.P.Doye,J.Phys.Chem.A 101,5111(1997)] to study the structural evolution of gold nanoclusters(N=3-20).The first modification in this modified BH(MBH)algorithm is to define a confined spatial volume within which the clusters lowest energy structure is to be searched.