S.A. Martin Britto Dhas

Spectral characterization of a non-centrosymmetric organic compound: D-(–)-alanine

The crystal growth of D-(-)-alanine (1), a non-centrosymmetric solid is reported. It was characterized by NMR, infrared, Raman, UV-Vis-NIR and CD spectra. Experimental vibrational frequencies are compared with theoretically calculated values. Second harmonic generation (SHG) and first hyperpolarizability measurements are reported.

Ferroelectric Behavior of Organic Terahertz Radiating DAST Crystal

Bulk terahertz emitting and technologically advanced DAST crystal is grown using a simple, cost effective and efficient seed rotation technique from a saturated methanol solution. The grown crystal is identified by a single crystal XRD analysis and powder X-ray diffraction studies. HRXRD experiments substantiate a good crystalline perfection without interior grain boundaries. The ferroelectric nature of the crystal has been described by P–E hysteresis loop analysis, which corroborates with better ferroelectric behavior than other benchmarked inorganic materials. The hardness, elastic stiffness, and yield strength shows decreasing trend for increasing loads and the work hardening coefficient confirm that the DAST is a soft material. Two-dimensional nucleation growth with minimum dislocation is evident from the etch patterns.