Papri Chakraborty, a Research Scholar from IIT Madras along with her colleagues, under the guidance of Professor T Pradeep and Chair Professor Deepak Parekh from the Department of Chemistry, had conducted a research in which they had found that atoms in metals like old and silver actually do not move as a result of which they are stable and noble.
They had observed through their experiment that the chemical and physical processes do not let the atoms move between particles easily. The team had conducted an experiment where they had prepared 1 nanometre particles of silver called clusters that are composed of 25 atoms which have been protected with molecules called ligands. In order to test the hypothesis of atom transfer, the team of researchers prepared 25 identical atom clusters with two isotopes of silver (107Ag and 109Ag). They mixed these two clusters in solution and measured the mass spectrum in solution. Upon performing this experiment, the researchers found that the parent clusters somehow vanished completely and a new cluster of 25 atoms (mixture of 107Ag and 109Ag atoms) got emerged. This result was similar as the formation of a molecule of HDO when H2O and D2O are mixed because H and D atoms exchange each other when normal water (H2O) and heavy water (D2O) are mixed. This behaviour of atoms also referred as 'dance of atoms' is same as in water molecules where protons (hydrogen nuclei) move in between water (H2O) molecules, even down to very low temperatures. However as a result of this movement, to some extent pure water and ice are electrically-conducting. During the experiment it has been observed that atom transfer rate is similar to that in water. The spontaneous atom transfer in nanoparticles show their molecular nature and atoms at the surface of such particles could be interacting with neighbouring particles same as in molecules. This research has been important because as per Professor Pradeep it question the fundamental idea of the behaviour of nanoparticles in solutions. Papri Chakraborty had mentioned that "our study answers fundamental questions regarding the dynamics and interconversions of nanoparticles. It is really very amazing to find out that nanoparticles can behave as simple molecules, just as water." Pradeep also said that "In case of homogeneous catalysis, an important application of nanomaterials -- the site on the nanoparticles at which chemistry occurs -- could be changing spontaneously. The dynamics is indeed of key importance in the field of biology where nanoparticles are used as drug carriers."
By: Anuja Arora