Isotope effects in aqueous solvation of simple halides

P. J. ROSSKY; P. E. VIDELA; LARIA, DANIEL H.

JOURNAL OF CHEMICAL PHYSICS

AMER INST PHYSICS

Lugar: New York; Año: 2018 vol. 148 p. 102306 - 102306

0021-9606

We present a path-integral-molecular-dynamics study of thethermodynamic stabilities of DOH$cdots$ X$^-$and HOD$cdots$X$^-$ [X = F, Cl, Br, I] coordination in aqueoussolutions at ambient conditions.  In agreement with experimental evidence,our results for the F$^-$ case reveal a clear stabilization of thelatter motif whereas, in the rest of the halogen series, the formerarticulation prevails. This preference becomes more marked, the larger the sizeof the ionic solute.  A physical interpretation of these tendencies{color{red}is provided in terms of an analysis of the global quantum kinetic energies}of the light atoms and their geometrical decomposition. The stabilization ofthe alternative ionic coordination geometries is the result of adelicate balance arising fromquantum spatial dispersions along parallel and perpendiculardirections with respect to  the relevant O-H${m cdots X^-}$ axis.This interpretation iscorroborated by a complementary analysis performed on the differentspectroscopic signals of the corresponding IR spectra.