• H C Joshi

Articles written in Pramana – Journal of Physics

• Influence of donor-donor transport on excitation energy transfer

Energy migration and transfer from acriflavine to rhodamine B and malachite green in poly (methylmethacrylate) have been investigated using the decay function analysis. It is found that the influence of energy migration in energy transfer can be described quite convincingly by making use of the theories of Loring, Andersen and Fayer (LAF) and Huber. At high acceptor concentration direct donor-acceptor transfer occurs through Förster mechanism.

• Dynamics of the multispecies colliding plasmas of different atomic masses

Laser-produced plasma plumes and the subsequent interaction zone of multispecies colliding plasmas have been investigated in vacuum (at 5 × 10$^{−7}$ mbar) by using Nd:YAG nanosecond laser as the energy source.The key features such as shape, size, expansion dynamics of the primary plumes and the resulting interaction zone have been examined by using a combination of solid targets (e.g. Al–Ni and Al–W) with different atomic masses. Fast imaging technique has been utilised to visualise the formation and expansion dynamics of the primary plasma plumes as well as the interaction zone. Optical emission spectroscopy (OES) is used to estimate the electron temperature and density of the plasma plumes. Optical time of flight has been used to get the velocity of ion and neutral particles in the plasma plume. Time-resolved images of plumes show significant differences depending on the target materials and energy of the two beams. We have observed that the primary plasma plumes withnon-uniform expansion velocity produces interaction zone which expands at an angle in vacuum. Optimisation of laser energy imbalance has been done based on fast imaging results for the targets of different elements. These experimental findings can have important roles in the generation of multispecies plasma plumes and to control their species contribution in different applications, e.g. thin film deposition.

• # Pramana – Journal of Physics

Volume 96, 2022
All articles
Continuous Article Publishing mode

• # Editorial Note on Continuous Article Publication

Posted on July 25, 2019