TY - JOUR
T1 - How Many Water Molecules Does it Take to Dissociate HCl?
AU - Vargas-Caamal, Alba
AU - Cabellos, Jose Luis
AU - Ortiz-Chi, Filiberto
AU - Rzepa, Henry S.
AU - Restrepo, Albeiro
AU - Merino, Gabriel
N1 - Publisher Copyright:
© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
PY - 2016/2/18
Y1 - 2016/2/18
N2 - The potential energy surfaces of the HCl(H2O)n (n is the number of water molecules) clusters are systematically explored using density functional theory and high-level ab initio computations. On the basis of electronic energies, the number of water molecules needed for HCl dissociation is four as reported by some experimental groups. However, this number is five owing to the inclusion of entropic factors. Wiberg bond indices are calculated and analyzed, and the results provide a quadratic correlation and classification of clusters according to the nondissociated, partially dissociated, and fully dissociated character of the H-Cl bond. Our computations show that if temperature is not controlled during the experiment, the values obtained for the dipole moment (or for any measurable property) are susceptible to change, providing a different picture of the number of water molecules needed for HCl dissociation in a nanoscopic droplet. Acid dissociation: High-level ab initio and DFT computations show that four water molecules are needed for HCl dissociation, but this number increases to five if entropic factors are considered (see figure). The temperature affects the dipole moments obtained, giving a different picture of the number of water molecules needed for HCl dissociation in a nanoscopic droplet.
AB - The potential energy surfaces of the HCl(H2O)n (n is the number of water molecules) clusters are systematically explored using density functional theory and high-level ab initio computations. On the basis of electronic energies, the number of water molecules needed for HCl dissociation is four as reported by some experimental groups. However, this number is five owing to the inclusion of entropic factors. Wiberg bond indices are calculated and analyzed, and the results provide a quadratic correlation and classification of clusters according to the nondissociated, partially dissociated, and fully dissociated character of the H-Cl bond. Our computations show that if temperature is not controlled during the experiment, the values obtained for the dipole moment (or for any measurable property) are susceptible to change, providing a different picture of the number of water molecules needed for HCl dissociation in a nanoscopic droplet. Acid dissociation: High-level ab initio and DFT computations show that four water molecules are needed for HCl dissociation, but this number increases to five if entropic factors are considered (see figure). The temperature affects the dipole moments obtained, giving a different picture of the number of water molecules needed for HCl dissociation in a nanoscopic droplet.
KW - ab initio calculations
KW - dissociation
KW - global optimization
KW - hydrogen bonds
KW - microsolvation
UR - http://www.scopus.com/inward/record.url?scp=84958291875&partnerID=8YFLogxK
U2 - 10.1002/chem.201504016
DO - 10.1002/chem.201504016
M3 - Artículo
AN - SCOPUS:84958291875
SN - 0947-6539
VL - 22
SP - 2812
EP - 2818
JO - Chemistry - A European Journal
JF - Chemistry - A European Journal
IS - 8
ER -