  Although liquid water is ubiquitous in chemical reactions at roots of life
and climate on the earth, the prediction of its properties by high-level ab
initio molecular dynamics simulations still represents a formidable task for
quantum chemistry. In this article we present a room temperature simulation of
liquid water based on the potential energy surface obtained by a many-body wave
function through quantum Monte Carlo (QMC) methods. The simulated properties
are in good agreement with recent neutron scattering and X-ray experiments,
particularly concerning the position of the oxygen-oxygen peak in the radial
distribution function, at variance of previous Density Functional Theory
attempts. Given the excellent performances of QMC on large scale
supercomputers, this work opens new perspectives for predictive and reliable
ab-initio simulations of complex chemical systems.
