Measurement of infrared transition of NH3 from a microwave line shift due to a non-resonance infrared field

An IR spectroscopic technique is proposed which may be useful for the determination of IR transitions and for the assignment of molecular spectra. This method is based on the microwave line shift in the presence of a non-resonant laser field. For NH3 gas, the accuracy is of about the same order of magnitude as the one obtained from the IR Stark spectroscopy technique.