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Fundamental Change in the Nature of Chemical Bonding by Isotopic Substitution
Author(s) -
Fleming Donald G.,
Manz Jörn,
Sato Kazuma,
Takayanagi Toshiyuki
Publication year - 2014
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201408211
Subject(s) - isotopomers , kinetic isotope effect , chemistry , van der waals force , chemical bond , methanethiol , atom (system on chip) , computational chemistry , hydrogen bond , chemical physics , deuterium , atomic physics , molecule , sulfur , physics , organic chemistry , computer science , embedded system
Isotope effects are important in the making and breaking of chemical bonds in chemical reactivity. Here we report on a new discovery, that isotopic substitution can fundamentally alter the nature of chemical bonding. This is established by systematic, rigorous quantum chemistry calculations of the isotopomers BrLBr, where L is an isotope of hydrogen. All the heavier isotopomers of BrHBr, BrDBr, BrTBr, and Br 4 HBr, the latter indicating the muonic He atom, the heaviest isotope of H, can only be stabilized as van der Waals bound states. In contrast, the lightest isotopomer, BrMuBr, with Mu the muonium atom, alone exhibits vibrational bonding, in accord with its possible observation in a recent experiment on the Mu+Br 2 reaction. Accordingly, BrMuBr is stabilized at the saddle point of the potential energy surface due to a net decrease in vibrational zero point energy that overcompensates the increase in potential energy.