NMR determination of the Sternheimer antishielding factor of Ca2+.
The experimental determination of the Sternheimer antishielding factor gamma(infinity) for Ca2+ in a sold material is reported for the first time. The gamma(infinity) value was obtained by comparing the quadrupole frequency measured by 43Ca NMR with the electric field gradient calculated in a frame of the point charge approximation in the high-Tc superconducting compound, Tl0.5Pb0.5Sr2CaCu2O7. The deduced value (gamma(infinity)= -6.1+/-.9) is about one-third of that obtained from the quantum mechanical calculations, whereas in the same sample, the gamma(infinity)value for O2- deduced by the same procedure (gamma(infinity)= -13.7+/-2.0) is very close to the calculated one.
Trokiner
A
A
Laboratoire P.M.M.H., CNRS ULMR 7636, ESPCI, Paris, France. trokiner@pmmh.espci.fr
Bellot
P V
PV
Zhdanov
Y
Y
Yakubovskii
A
A
D002118:Calcium / Q000737:chemistry*; D002127:Calcium Isotopes; D002413:Cations, Divalent; D004574:Electromagnetic Fields; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*
D002127:Calcium Isotopes; D002413:Cations, Divalent; D002118:Calcium