Double infrared-microwave

K. O. Douglass, J. E. Johns, P. M. Nair, G. G. Brown, F. S. Rees, and B. H. Pate, Applications of Fourier transform microwave (FTMW) detected infrared microwave double resonance spec troscopy to problems in vibrational dynamics. J. Mol. Spectrosc. 239, 29 40 (2006). 

Fig. 5.12 Infrared-microwave double resonance in NHs. The microwave transitions between the inversion doublets can start from the laser-pumped level (signal S) or from levels where the depletion has been transferred by collisions (secondary DR signals S S") [534]...

Fig. 5.13 Infrared-microwave double resonance in the vibrationally excited V2 = l state of DCCCOH. The solid arrows indicate the microwave transitions, the wavy arrows secondary MW transitions [535]...

The experimental development of infrared-microwave double resonance was paralleled by the elaboration of the theoretical framework. For example, Shimizu published a theory of two-photon Lamb dips, and Takami theoretically described the optical-microwave double resonance with emphasis to fundamental aspects and the double resonance with microwave detection, and with optical detection. Detailed information on the theory of infrared-microwave double resonance can also be found in Refs. 216, 225-227. 

Meth. MW MBER Last IRIRDR IRMWDR method of measurement for ft microwave spectroscopy molecular beam electric resonance Laser Stark spectroscopy infrared-infrared double resonance infrared-microwave double resonance... 

Further examples and experimental details on infrared-microwave double-resonance spectroscopy can be found in [10.29-32]. 

Fig. 8.33. Infrared-microwave double resonance in NH3. S, S, and S" are microwave transitions between the inversion sublevels. The wavy arrows indicate collision induced transitions [8.88]...

Infrared, Raman, microwave, and double resonance techniques turn out to offer nicely complementary tools, which usually can and have to be complemented by quantum chemical calculations. In both experiment and theory, progress over the last 10 years has been enormous. The relationship between theory and experiment is symbiotic, as the elementary systems represent benchmarks for rigorous quantum treatments of clear-cut observables. Even the simplest cases such as methanol dimer still present challenges, which can only be met by high-level electron correlation and nuclear motion approaches in many dimensions. On the experimental side, infrared spectroscopy is most powerful for the O—H stretching dynamics, whereas double resonance techniques offer selectivity and Raman scattering profits from other selection rules. A few challenges for accurate theoretical treatments in this field are listed in Table I. 

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