"Vibrational bonding": a new type of chemical bond is discovered. (1st March 2015)

• Record Type: Journal Article
• Authors: Rhodes, Christopher; Macrae, Roderick
• Is Part Of: Science progress. Volume 98:Number 1(2015)
• Page Start: 12
• Page End: 33
• Publication Date: 2015-03-01
• Subjects: Science -- Periodicals; Research; Science; Science; Electronic journals; Periodicals; Periodicals; 505
• DOI: 10.3184/003685015X14232279560803
• Languages: English
• ISSNs: 0036-8504

Abstract

A long-sought but elusive new type of chemical bond, occurring on a minimum-free, purely repulsive potential energy surface, has recently been convincingly shown to be possible on the basis of high-level quantum-chemical calculations. This type of bond, termed a vibrational bond, forms because the total energy, including the dynamical energy of the nuclei, is lower than the total energy of the dissociated products, including their vibrational zero-point energy. For this to be the case, the ZPE of the product molecule must be very high, which is ensured by replacing a conventional hydrogen atom with its light isotope muonium (Mu, mass = 1/9 u) in the system Br – H – Br, a natural transition state in the reaction between Br and HBr. A paramagnetic species observed in the reaction Mu + Br2 has been proposed as a first experimental sighting of this species, but definitive identification remains challenging.