Study on the THz spectrum of methamphetamine

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Computational Chemistry

Background:

• Methamphetamine (MA) is a widely consumed illicit drug.
• Accurate detection methods for illicit substances are crucial for law enforcement and public safety.

Purpose of the Study:

• To investigate the spectral absorption features of methamphetamine (MA) using Terahertz (THz) time-domain spectroscopy (THz-TDS).
• To correlate experimental THz absorption spectra with theoretical vibrational frequencies calculated via density functional theory (DFT).

Main Methods:

• Experimental measurement of MA spectral absorption in the 0.2–2.6 THz range using THz-TDS.
• Computational calculation of MA vibrational frequencies using DFT.
• Comparison of experimental and theoretical results for mode identification.

Main Results:

• Characteristic absorption spectra of MA were obtained in the THz range.
• DFT calculations showed significant agreement with experimental spectral data.
• Identified specific vibrational modes contributing to the characteristic THz absorption frequencies.

Conclusions:

• THz-TDS is a viable technique for identifying methamphetamine.
• The study confirms that collective vibrational modes are responsible for MA's characteristic THz absorption.
• THz-TDS shows promise as an effective tool for illicit drug inspection.