DEMONSTRATING THE SPATIAL-RESOLUTION OF FIELD GRADIENT NMR

In recent years, field gradient NMR has become a method of increasing importance in measuring very small dislocations of molecules. Rough es timations indicate that, by utilizing large field gradients, one shoul d be able to detect motions down to the 10-nm scale. However, this lim it has not yet been experimentally detected. In this paper, we present a method that allows the direct measurement of the spatial resolution of field gradient NMR. For our experimental setup, utilizing an extre mely large static field gradient of about 180 T m(-1), we find a lower limit of 7 nm, thus for the first time confirming the expected resolu tion. Furthermore, we discuss the effect of unwanted vibrations as a l imiting factor Of the method. (C) 1998 Academic Press.