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Acetylcholine in water: Ab‐initio potential and Monte Carlo simulation
Author(s) -
Margheritis C.,
Corongiu G.
Publication year - 1988
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/jcc.540090102
Subject(s) - chemistry , monte carlo method , dihedral angle , ab initio , computational chemistry , basis set , molecular dynamics , ab initio quantum chemistry methods , ion , molecule , thermodynamics , hydrogen bond , physics , density functional theory , statistics , mathematics , organic chemistry
Ab initio SCF‐LCAO‐MO computations using a minimal basis set have been carried out on the acetylcholine ion in different conformations. The rotational barrier around the C9‐C8‐O1‐C2 dihedral angle (τ 1 ) has been also calculated: the curve presents a broad minimum. SCF calculations have been carried out on the system Ach‐water at 468 different separations and/or orientations; the interaction energies were then fitted to a pair potential function used in Monte Carlo (MC) simulations of Ach water solution. The rdfs indicate a global first hydration shell with about 38 waters. Details about the hydration shell are presented. The overall MC results indicate that for the Ach ion in water solution at room temperature relative free rotation is possible around τ 1 , and that Ach is well represented as a large positively charged hydrated globe with a small mobile tail free of strong interactions with the surrounding water molecules.