Mumbai: Scientists of Kalpakkam-based Indira Gandhi Centre for Atomic Research in Tamil Nadu have done a study of pure Uranium using Raman Spectroscopy, the
first study of its kind in the world.
Study of metals by Raman Spectroscopy is a challenging
scientific problem due to the low penetration of laser into
metals and hence low sampling volumes.
"Considering the Raman spectra of metals have not
been studied widely owing to their weak spectral intensities,
work on Raman Spectra of Uranium to understand its structural
properties is a significant step, Dr T R Ravindran of the
Condensed Matter Physics Division said.
Many metals that crystallise in face centred cubic
(fcc) or body centred cubic (bcc) structures, do not have
Raman active modes, and hence out of the purview of Raman
spectroscopy, he said.
An enhancement of signal is achieved by a Surface
Enhanced Raman Scattering technique in a novel geometry,
utilising a thin coating of a few nanometres of gold on
Uranium with surface scratches and pits of dimensions of
several nanometres, Ravindran said in the journal of Raman
Spectroscopy and latest newsletter of Indira Gandhi Centre for
Atomic Research (IGCAR).
Technologically important actinide metals like Uranium
and plutonium have not been investigated using Raman
spectroscopy due to poor signal intensities and the present
work opens up possibility this technique can be used to study
other metals and materials of weak Raman intensity, Ravindran
and his colleagues said ICGAR is the second largest establishment of the
Department of Atomic Energy after Bhabha Atomic Research
Centre for conducting broad-based scientific research into the
development of sodium-cooled Fast Breeder Reactor [FBR]
Replying to a query on Raman weak intensity and how it
will help the study of materials or metals in their future
use, Ravindran said, "Raman scattering is a weak effect; we
need very sensitive instruments to record Raman spectra; even
then there are a large number of materials that do not give
intense Raman spectra and hence difficult to study."
For example, special techniques such as Surface
Enhanced Raman Scattering (SERS) or Resonance Raman scattering
(that can be achieved by changing the laser excitation
wavelength) need to be employed in case of metals, he said.
At present the study, though significant, is in the
realm of basic research. Applications of this will be known
only when further studies and analyses are done, he added.