Аннотация:The work presents algorithms and results of the direct computational experiment on mathematicalmodeling of water clusters treated as quantum systems numerically described using the corresponding Schrödinger equation. The method earlier developed by the author for Monte Carlo numerical solution of the Schrödinger equation is used. This method has proved itself to be quite time-efficient. Its input data are averagepositions of particles in a quantum system, for description of which a second method is developed. Several energy isomers of water clusters are found by the method for construction of average positions of quantumsystem particles. The energy isomers of the water dimer, trimer, and hexamer given in the work are regarded as possible geometrical structures of water clusters and illustrate the use of the proposed methods for calculation of quantum systems.