Quantum molecular dynamics of hydrogen bonded complexes of rigid molecules using the semiclassical initial value representation in Cartesian coordinates

Abstract

Semiclassical initial value representation calculations are performed for the constrained water dimer in Cartesian coordinates. The study represents the first application of a previously reported method [Issak and Roy, J. Chem. Phys. 123, 084103 (2005); 126, 024111 (2007)] to a molecular cluster. Bound state energies are calculated for a dimer of rigid water molecules (H2O)2 as well as its deuterated form (D2O)2. The results show that the approach fares well with respect to accuracy in capturing quantum effects in intermolecular interactions.

Accelerated direct semiclassical molecular dynamics using a compact finite difference Hessian scheme

“…For these reasons, our understanding is that the present numerical approximation of the SC-IVR propagator represents a significant step forward with respect to other monodromy matrix approximations. 11,19,50,52,83 …”

“…[1][2][3] In particular, semiclassical initial value representation (SC-IVR) theories have proven to be quite accurate, as demonstrated by numerous applications. [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] The fundamental advantage of the SC-IVR propagator over basis set evaluations of the quantum propagator, such as the multiconfigurational time-dependent Hartree 21 or the coupled coherent states methodology, 22 is that it exclusively relies on classical trajectories and, therefore, it can be straightforwardly implemented with "on the fly" direct molecular dynamics calculations. In addition, basis sets and other 23,24 approximate evaluations of the quantum propagator need a global potential energy surface, while SC-IVR depends only on the local potential.…”

Fighting the curse of dimensionality in first-principles semiclassical calculations: Non-local reference states for large number of dimensions

“…44 This simulation provides a good benchmark for different first-principles semiclassical molecular dynamics approaches. The formaldehyde molecule is a well tested system, in particular, at the semiclassical and vibrational configuration interaction (VCI) level.…”

“…24,[35][36][37][38][39][40][41][42][43][44][45][46] In the Heller-Herman-KlukKay 25,47 version of the SC-IVR, the pre-exponential factor,…”

Linearized semiclassical initial value time correlation functions with maximum entropy analytic continuation

“…The SC-IVR provides a way for generating the quantum time evolution operator (propagator) by computing an ensemble of classical trajectories, much as is done in standard classical MD simulations. As is well known from SC developments in the early 1970's 1,[18][19][20][21] , such approaches actually contain all quantum effects at least qualitatively, and in molecular systems the description is usually quite quantitative (see reviews [2][3][4][5]14,22,23 and some recent applications [24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] ).…”