A METHOD FOR DETERMINATION OF NMR
SIGNAL RESONANCE FREQUENCIES AND DETECTION
OF THE EFFECTS OF ISOTOPIC SUBSTITUTION
OF NUCLEI IN HYDROGEN MOLECULES
Yu. I. Neronov, S. G. Karshenboim
Saint-Petersburg State University of Information
Technology, Mechanics and Optics;
D.I. Mendeleev All-Russia Research Institute of Metrology, Saint-Petersburg
The paper presents a method for determination
of NMR signal frequencies with visual monitoring of optimal separation of
radio-frequency signals into real and imaginary parts. The software package
developed in this work employs minimization of standard deviations from the
calculated profile for both NMK signal components, which provides the statistical
error of frequency measurement (delta nu/nu) at the
level of about 10^-9 for high magnetic field spectrometers. The method was
applied to define chemical shifts at isotopic substitution of hydrogen atoms
DELTAsigma = sigma(D2)-sigma(DH)
with a search for non-linear effects using magnetic fields В = 7.049 and
В = 11.747 Т.