Inorganic Spectra

Abstract

To record a normal FT NMR spectrum we apply a pulse to our spin system and record the free induction decay (FID) following the pulse. The spectrum is obtained by Fourier Transform where the time dependent FID is converted to a function of frequency, i.e., an NMR spectrum. 2D NMR spectroscopy records a spectrum as a function of two characteristic times. Many FIDs are recorded as a function of a systematically varied delay time. The typical two-dimensional NMR experiment has three phases; during the preparation phase the system is allowed to relax; then a 90° pulse is applied and the system is allowed to evolve as a function of a delay time, t 1 , which can be of the order of milliseconds to seconds; then another 90° pulse is applied and the free induction is recorded as a function of time, t 2. The series of experiments yields an array of data as a function of two times. The array is subjected to two consecutive Fourier transformations, the first giving a series of NMR spectra with different delay times, the second