傳統的傅立葉轉換紅外光譜儀(FTIR)無法偵測生命期短的不穩定化合物。吾人利用步進式的FTIR，並配合ac/dc耦合的偵測器及多重反射之紅外吸收和紫外光解，成功地建立了時域解析的FTIR吸收光譜法，得以在實驗室偵測以傳統方法不易測得的許多大氣化學中重要的不穩定氣態化合物，如ClCO、ClCS、ClSO、CH3SO2、C6H5SO2、CH3OO、ClCOOH、CH3SO及CH3C(O)OO，並分析其紅外吸收光譜。此系統具有10ns之時域解析度及0.13cm^(-1)之光譜解析度，但在吾人之實驗中，通常使用1μs之時域解析度及1cm^(-1)之光譜解析度，以得到較理想之光譜。

Conventional Fourier-transform infrared spectrometer (FTIR) cannot detect species with short lifetime. We employed step-scan FTIR coupled with ac/dc detection and multiple reflection of both IR probe beam and UV photolysis beam to establish time-resolved FTIR absorption spectrometry so as to detect in the laboratory several unstable gaseous species that are important in atmospheric chemistry: ClCO, ClCS, ClSO, CH3SO2, C6H5SO2, CH3OO, ClCOOH, CH3SO, and CH3C (O) OO via their IR absorption. The system is capable of 10 ns temporal resolution and 0.13 cm^(-1) spectral resolution, but for radical studies we typically employed 1μs temporal resolution and 1 cm^(-1) spectral resolution to obtain spectra with improved S/N ratio.