Our group is involved with new materials. Most often the constituents of these materials are 'nano' objects. We explore the possibility of discovering novel physical and chemical properties of these objects. Some of these investigations have led to viable technologies.We are also interested in soft materials such as ice, especially the surface of ice, where we have found new phenomena.
Our studies contributed to the understanding of the structure of molecules in nanoscale assemblies. We discovered new reactions of materials at the nanoscale and developed novel applications of nanoparticles. A product based on our research has already been commercialized.
We discovered a new oscillatory phenomenon on ice surfaces and found that kinetic barriers can arrest even simplest reactions on them. Most recently we have shown that diffusion of molecules through ice brings out surprises, which have implications to the chemistry of ice particles.
For all these studies we have developed state-of-the-art scientific instrumentation.
Clusters / Aspicules
Sub-nanometer-sized metal clusters, having dimensions between metal atoms and nanoparticles, have attracted tremendous attention in the recent past due to their unique physical and chemical properties. As properties of such materials depend strongly on size, development of synthetic routes that allows precise tuning of the cluster cores with high monodispersity and purity is an area of intense research. Such materials are also interesting owing to their wide variety of applications. Novel sensing strategies based on these materials are emerging. Owing to their extremely small size, low toxicity, and biocompatibility, they are widely studied for biomedical applications. We synthesize different types of such clusters, characterize them and study their properties.
Ion Chemistry / Mass Spectrometry
Recent progress in mass spectrometry has depended heavily on advances in the methods of ion formation. The creation of stable molecular ions of complex molecules with minimum internal energy has been a primary goal of such experiments. The most widely used methods to achieve this are electrospray ionization (ESI) and matrix-assisted laser desorption/ionization (MALDI). More recently developed ambient ionization methods such as desorption electrospray ionization (DESI), allow samples to be examined in their native state with minimal or no sample pre-treatment. We use DESI to image molecular distribution in tissues, cells and plant parts. We also develop new methods to create ions at ambient conditions for various applications.
Water is one of the essential enablers of life on earth. Beginning with the origin of the earliest form of life in seawater, it has been central to the evolution of human civilizations. Recently, water quality has been associated with the development index of society. A number of chemical and biological contaminants have endangered the quality of drinking water. Realizing the molecular nature of contamination in drinking water, significant progress has been made to utilize the chemistry of nanomaterials for water purification. We synthesize different kinds of nanomaterials, mostly noble metal and carbon based, for treatment of water. We also make devices for water filtration from our materials and commercialize them.
Materials play a very important role in today’s world and we cannot simply imagine our daily life without different kinds of materials. While bulk materials like alloys, ceramics, etc. have contributed tremendously towards the development of civilizations, another kind of materials, namely nanostructured materials, are the backbones of modern day applications in electronics, medicines, devices, sensors, etc. We synthesize different kinds of nanomaterials and characterize them with the help of a bunch of spectroscopic and microscopic techniques. We also use them for applications like sensing, water purification, etc.
Understanding biological phenomena is one of the challenging tasks as biological objects and phenomena occurring in them are very complex. But unrevealing the processes occurring at biological systems have several implications towards mankind. It can help us to understand diseases, biomimicry several processes, etc. By combining different analytical techniques, we investigate plants for the distribution of different chemicals in them, cancer cells and their abnormality in chemical production compared to normal cell, nanoparticle-cell interaction, etc.
Extremely surface specific information, limited to the first atomic layer of molecular surfaces, is essential to understand the chemistry and physics in upper atmospheric and interstellar environments. Ultra low energy ion scattering in the 1–10 eV window with mass selected ions can reveal extremely surface specific information which when coupled with reflection absorption infrared (RAIR) and temperature programmed desorption (TPD) spectroscopies, diverse chemical and physical properties of molecular species at surfaces could be derived. These experiments have to be performed at cryogenic temperatures and at ultra high vacuum conditions without the possibility of collisions of neutrals and background deposition in view of the poor ion intensities and consequent need for longer exposure times. We use a highly optimized low energy ion optical system designed for such studies which have relevance to the interstellar phenomena.