화학공학소재연구정보센터
Journal of Chemical Physics, Vol.112, No.5, 2218-2226, 2000
Tunneling splittings in water trimer by projector Monte Carlo
We demonstrate the Monte Carlo calculation of multidimensional tunnel splittings in the water trimer without the use of explicit nodal approximations. The calculations are made for the three-dimensional torsional model of the nonbonded hydrogen atom motions. We employ the projection operator imaginary time spectral evolution (POITSE) method, which requires specification of a set of projector operators. The permutation symmetry leading to exchange tunneling is incorporated into these projectors directly. We analyze the optimal choice of the real space vibrational coordinates with a comparative study of local vs nonlocal symmetry-adapted nuclear coordinates. Extraction of the lowest four sets of tunneling states yields good agreement with available discrete variable representation calculations.