@misc{item_3332545,
  title = {{Coherent evolution of signal amplification by reversible exchange in two alternating fields (alt-SABRE)}},
  abstract = {{Parahydrogen (pH2) is a convenient and cost efficient source for magnetic resonance signal enhancement. Transient interaction of pH2 with a metal organic complex in a signal amplification by reversible exchange (SABRE) experiment enabled more than 10\textpercent polarization for some 15N molecules. Here, we analyzed a variant of SABRE, consisting of an outer magnetic field alternating between a low field of \textasciitilde1 \muT, where a polarization transfer takes place, and a higher field \textgreater50 \muT (alt-SABRE). We found effects of both of these fields on amplitude and the frequency of polarization transfer. Deviation of a lower magnetic field from a "perfect" condition of level anti-crossing increases the frequency of polarization transfer that can be exploited for polarization of short-lived transient SABRE complexes i.e. some substrates. Moreover, the coherences responsible for polarization transfer at a lower field persisted during magnetic field variation and continued their spin evolution at higher field with a frequency of 2.5 kHz at 54 \muT. The latter should be taken into consideration for an efficient alt-SABRE.}},
  year = {2021},
  slug = {item_3332545},
  author = {Pravdivtsev, AN and Kempf, N and Plaumann, M and Bernarding, J and Scheffler, K and H\"ovener, J-B and Buckenmaier, K}
}