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Record 1,  Textual support,  English

Record number: 1, Textual support number: 1 CONT

Exchange (intermediate, fast, slow, chemical and conformational): Exchange is a kinetic process between two (or more) states that is characterized by a rate constant. In NMR [nuclear magnetic resonance] spectroscopy, exchange is classified into fast, intermediate and slow depending on the size of the rate constant with respect to chemical shift (which is measured in the same units (Hz) as the rate constant). In the fast exchange regime, the rate is much larger than the difference in chemical shift between the two states and the NMR signal will be at the weighted average position of the two states. In slow exchange, signals for both states are observable and the intensities are proportional to the populations of the two states. In intermediate exchange, the transition between the signals seen for slow and fast exchange takes place, resulting in very broad and often non-observable signals.  1, record 1, English, - fast%20exchange

Record 1,  Textual support,  French

Record number: 1, Textual support number: 1 CONT

L’échange en RMN (résonance magnétique nucléaire) […] La cinétique de l’échange est déterminante. Considérons l’échange entre deux sites A [et] B dans l’hypothèse la plus simple […] Que signifient dans une première approche les expressions «échange rapide» et «échange lent» à l’échelle de temps de la RMN ? L’échange est dit lent s’il n’intervient pas significativement pendant l’acquisition des données […] : les deux sites sont alors observés à leurs fréquences caractéristiques. L’échange est dit rapide si un seul signal est observé : les aimantations n’acquièrent pas pendant le temps tau une différence de phase au moins égale à pi […]  1, record 1, French, - %C3%A9change%20rapide

Record 1,  Textual support,  Spanish