Analysis of Terahertz Absorption Spectra Characteristic of 1-Naphthaleneacetic Acid and 4-Chlorophenoxyacetic Acid in Terahertz Region

We firstly study terahertz time-domain spectroscopy (THz-TDS) characterization of two kinds of pesticides 1-naphthaleneacetic acid and 4-chlorophenoxyacetic acid. The absorption spectrum and refractive index of samples were measured. Theoretical investigation of the vibrational spectrum of pesticides was performed based on density function theory (DFT). We observed that experiment spectra are in rough qualitative agreement with these theory spectra. Its chemical composition was successfully identified through spectral analysis of the recorded terahertz waveform. These feature spectra measurements are helpful to form a database of pesticide.