Astrophysicists need accurate lifetimes of Ta II (5d+6s)^3 6p J=1 atomic states to determine the abundances of Ta+ ions in some chemically peculiar stars. There are experimental results for some of these lifetimes, but others have not yet been measured and are challenging to calculate. We have done extensive Relativistic Configuration Interaction (RCI) calculations for these odd parity states, and the (5d+6s)^4 J=0,1,2 even parity states to which they decay by electric dipole transitions. From our RCI wave functions, we have calculated lifetimes for the twelve lowest odd parity states, as well as Lande g-values and hyperfine structure constants for even and odd parity states. Our calculations and results will be presented in this talk, and compared with the available experimental values.

A study of two extreme motions in solids based on their potential applicability will be presented, the slow rotational motion of solid particles to understand the turbulence in fluids and the fast thermal motion of molecules in zeolites in the study of catalysis. A novel technique sensitive to rotational motion is developed here to observe the slow rotational motion of solid particles using single or multiple-pulse Nuclear Magnetic Resonance(NMR) techniques based on Zeeman perturbed nuclear quadrupole resonance (ZNQR) will be presented. A probe is designed to perform experiments on Br⁷⁹ nucleus in physically rotated (up to a maximum of 20Hz) powdered Cs₂ZnBr₄ sample placed in a small external magnetic field (a maximum of ~250G). A theoretical model has been worked out to understand Zeolites are well known for their application in the petroleum industry as catalytic agents. The study of fast thermal motion (>kHz) of adsorbed molecule in complex framed zeolite structure is a means to gain a better understanding about the catalytic process. Here, an investigation on the growth of the narrow component of the NMR lineshape for deuterium (H²) nuclei of acetonitrile adsorbed molecule in MFI-5 zeolite as a function of temperature is presented. Also, thermal motion of the adsorbed molecule corresponding to the narrow component based on spin-lattice relaxation time is discussed.