Intermolecular dipole-dipole relaxation of (129)Xe dissolved in water.
Intermolecular (129)Xe-(1)H nuclear Overhauser effects and (129)Xe longitudinal relaxation time measurements were used to demonstrate that the dipole-dipole coupling is the dominant relaxation mechanism for (129)Xe in water, at room temperature. (129)Xe-(1)H cross-relaxation rates were derived to be sigma(XeH) approximately 3.2 +/- 0.3 x 10(-3) s(-1), independent of xenon pressure (in the range of 1-10 bar) and of the presence of oxygen. Corresponding xenon-proton internuclear distances were calculated to be 2.69 +/- 0.12 A. Using the magnitude of the dipole-dipole coupling and the spin density ratio between dissolved xenon and bulk water, it is estimated that (129)Xe-(1)H spin polarization-induced nuclear Overhauser effects would yield little net proton signal enhancement in water.
Department of Biochemistry and Molecular Biophysics, University of Pennsylvania, Philadelphia 19104, USA.
I E
IE
Dimitrov
R
R
Reddy
J S
JS
Leigh
D000465:Algorithms; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D009682:Magnetic Resonance Spectroscopy; D014867:Water / Q000737:chemistry; D014978:Xenon / Q000737:chemistry*; D014979:Xenon Isotopes
D014979:Xenon Isotopes; D014867:Water; D014978:Xenon