Kernmagnetische Relaxation und Korrelation im System Wasser - Sauerstoff

Abstract

The magnetic interaction between the electronic magnetic dipole moment of molecular oxygen dissolved in water and water protons has been investigated by measuring the nuclear magnetic proton relaxation times and their dependence upon oxygen pressure (10–2—200 at), upon the proton LARMOR frequency (0.45 — 160 Mc) and upon temperature (20°C—300°C). The results are interpreted in terms of microscopic correlation times. The dipolar interaction, which is dominant, appears to be modulated in time mainly by the correlation time τS of the 02 electron spin. At 25°C we obtain τS = (1 ± 0.4) · 10-11 sec for the O2 spin correlation time and d= 2.87 ± 0.15 Å for the effective distance of nearest approach between electron and proton spin. The value for the translational correlation time TD > 1.3·10-11 sec at 25°C, somewhat larger than in pure water, might suggest a weak, short-lived bonding between O2 and H2O.