Dynamic infrared spectroscopy using the rapid-scan technique

A technique using rapid-scan Fourier transform infrared (FT-IR) spectroscop y to observe reversible dynamic changes of systems under an externally appl ied perturbation is introduced. The technique does not require a lock-in am plifier or synchronization between the applied perturbation and the spectra l acquisition. With the use of a carefully designed sampling rate with resp ect to the perturbation period and reconstruction of the observed spectral intensities, dynamic spectral intensities of the system are obtained. Due t o the repeated behavior, the reconstructed spectral intensities can be used to represent the dynamic characteristic of the system. The experimentation time of the rapid-scan technique is significantly shorter than that of the step-scan technique. The influences of noise and experimental parameters o n the observed spectral intensities are verified. Applications of the techn ique to systems with sinusoidal dynamic changes and exponentially decaying dynamic changes are demonstrated.