TRAPDOR transfer of population

It was shown that REDOR or its variants can be used when one coupling partner is a quadrupolar spin.113,114 However, there are some limitations, such as the fact that only a fraction of the spin-1, nuclei are involved in the dephasing.115 Accordingly, more specific dephasing methods have been proposed for this type of system. One is TRAPDOR (transfer of population in double resonance), which uses continuous irradiation.116 The other is REAPDOR (rotational-echo, adiabatic passage, double resonance),117,118 which is a more straightforward extension of REDOR. 

HETCOR), MQ REDOR (Rotational Echo Double Resonance), TRAPDOR (TRAnsfer of Populations in DOuble Resonance) and REAPDOR (Rotational Echo Adiabatic Passage Double Resonance), and the recently introduced /-cou-phng based experiments. A few other excellent reviews on MQMAS NMR have been recently pubhshed and complement the present review [1,2]. 

TRAPDOR Transfer of populations double resonance u.c. Unit cell... 

The REDOR experiment has been proposed for spin-1/2 pairs. For quadmpolar nuclei-spin-1/2 pairs, the use of this experiment is limited. The main reason behind this is the fact that a significant quadmpolar broadening (in order of several MHz) makes the Sn pulses inefficient for the inversion of S populations. For such systems REDOR experiments can be applied if the n pulses are apphed to the spin-1/2 nucleus and only central transition is observed for a halfinteger spin. The transfer of population in double resonance (TRAPDOR) or rotational-echo adiabatic passage double resonance (REAPDOR) experiment offer a much better choice for the measurement of quadmpolar nuclei-spin-1/2 pair dipolar couplings. 

Solid-state NMR spectroscopy has been demonstrated as a well established technique for characterization of zeolites and other porous materials with respect to structure elucidation, pore architecture, catalytic behaviour and mobility properties. The latest progress in the development of NMR techniques, both with respect to software and hardware improvements, has contributed to the present state of the art for NMR within the field of characterization of zeolitic materials. Furthermore, the introduction of NMR imaging (110), two-dimensional quintuple-quantum NMR spectroscopy (111) and transfer of populations in double resonance (TRAPDOR) NMR (112,113) will extent the horizons of zeolite characterization science. As a final example, the Al => Si TEDOR experiment directly proves, for the first time, that silicon substitutes for phosphorous atoms in the framework of SAPO-37 (114). The Al... 

Many multiple resonance methods such as cross-polarisation (CP), Rotational Echo Double Resonance (REDOR), and Transferred Echo Double Resonance (TEDOR) are available. Their application can be differentiated between systems involving exclusively spin- /2 nuclei and those containing quadrupolar nuclei. The presence of quadrupolar nuclei may prohibit straightforward application of these experiments and can affect the interpretation of the results. There are, however, benefits arising from the presence of quadrupolar nuclei, as illustrated by the Transfer of Populations by Double Resonance (TRAPDOR) experiment which will only work for quadrupolar nuclei. 

Simultaneous structural correlations between P and Na nuclei and between P and Cs nuclei in a series of mixed-alkali sodium-cesium phosphate glasses were investigated by transfer of populations via double resonanee (TRAPDOR) NMR spectroscopy. ... 

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