th  - 1988 - 51st ENC Conference

THU 10"2S I
NEW TECHNIQUES POR
DYNAMIC NUCLEAR POLARIZATION
W.Th. WENCKEBACH
KAMERLINGH ONNES LABORATORY, P.O.BOX 9506,
2300 RA LEIDEN, THE NETHERLANDS
Two new techniques for dynamic nuclear polarization have recently been
developed: Microwave induced optical nuclear polarization (MIONP) and
nuclear orientation via electron spin lock (NOVEL). In the first technique
photoexcited states with an electron spin are used to polarize nuclear spins.
As in classical dynamic nuclear polarization the electron spin polarization
k transferred to the nuclear spins using cw microwave irradiation. In the
second technique the electron spin polarization is transferred by means of
pulsed microwave techniquea First the electron spin is locked by a ~-pulse
followed by a ~--phase shift. Then the nuclear spins and the electron spins
are brought to mutual resonance by choosing the Rabi frequency of the
latter equal to Larmor frequency of the former. As a result polarization
tr-~uffer ~ obee~ed.
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