Terahertz spectroscopy--a new method for free radical detection

Terahertz spectroscopy is a new useful technique based on femto-second technology. With its unique frequency range, the technique has been applied to detection and analysis of gas free radicals and reactive molecules which are usually difficult to be measured by alternative methods. In this paper, we briefly introduce THz spectroscopy to detect free radicals and measure gas-phase molecules with high accuracy and its applications in studies on solution dynamics and charge transfer. (authors)