According to the researchers, transition metal silicides demonstrate superior oxidation resistance, high temperature stability and low corrosion rates, which make them promising for a variety of future electronic devices.
Fundamental aspects of the chemical bonding between their transition metal atoms and silicon remain poorly understood, however, including the strength of these chemical bonds – the thermochemical bond dissociation energy.
The team measured the energy at which the diatomic silicides fall apart more quickly than they can be ionised by absorption of a second photon. This amount of energy is called the predissociation threshold.
The researchers found that for molecules with certain electron configurations, if the molecule is cold, then the observation of a predissociation threshold provides an accurate value of the thermochemical bond dissociation energy, and not simply an upper limit.
“What I’m so pleased about with this new technique that we’ve developed is that it’s not just applicable to a small set of molecules,” said Professor Michael Morse, pictured.
“It’s based on the fact that these small transition metal molecules have a density of electronic states that increases very rapidly as you get close to the dissociation limit, and that’s key in causing the molecule to fall apart as soon as you get above that limit. The peculiarities of the transition metals make the method broadly applicable to that entire class of molecules.”
This sharp threshold observation is therefore said to provide a highly effective means of estimating the bond dissociation energy for transition metals bonded to other p-block elements.
