Cognitions on the effects of swift heavy ion irradiation on the dielectric and optical behaviour in l-asparaginium picrate

Organic nonlinear optical crystal l-asparaginium picrate was subjected to 100 MeV Ag8+ ions and 100 MeV Si8+ ions. The dielectric properties of the crystals were studied before and after irradiation from 100 Hz to 5 MHz at various temperatures (308 K to 358 K). A drastic increase in the dielectric constant is seen due to irradiation. The dielectric constant and dielectric loss increase with increasing irradiation fluence. The UV–vis spectra of the pristine and irradiated samples were recorded and quantified. There is a small shift in absorption edge towards lower wavelength for the irradiated crystals due to the decrease in bandgap of the material. The observed results are discussed in detail.