lecture_14_Introduction and Application of NMR Spectroscopy

lecture_14_Introduction and Application of NMR Spectroscopy...

Info iconThis preview shows pages 1–7. Sign up to view the full content.

View Full Document Right Arrow Icon
Lecture #14 Nuclear Magnetic Resonance (NMR) Spectroscopy: Introduction and Application Reading: Chapter 19, page 498 –549 Problems: 19-3,4,21-32. • Basics of NMR spectroscopy; • Quantum and classical description of NMR; • Types of NMR spectra and the environmental effects; • Analysis of spin-spin splitting; • Basic components of NMR spectrometer; • Qualitative and quantitative application.
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Some remarks about NMR Bloch (Stanford) and Purcell (Harvard) independently discovered NMR phenomenon in 1946, and shared the Nobel Prize in 1952. • In 1953, 1 st high-resolution NMR spectrometer was marketed by Varian. • Since 1970’s, FT-NMR has been commercially available and dominated the NMR application. • Can be applied to gaseous, liquid, and solid samples. • Four nuclei are widely used for NMR measurement: 1 H, 13 C, 19 F, 31 P. Nucleus (not electrons) are involved in NMR absorption process. NMR is highly demanded for organic chemistry as a routine technique for structural analysis.
Background image of page 2
The Nobel Prize in Physics 1952 "for their development of new methods for nuclear magnetic precision measurements and discoveries in connection therewith" b. 1912 d. 1997 b. 1905 (in Zurich, Switzerland) d. 1983 Harvard University Cambridge, MA, USA Stanford University Stanford, CA, USA USA USA 1/2 of the prize 1/2 of the prize Edward Mills Purcell Felix Bloch
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Quantum description of NMR • Nucleus spins and has an angular momentum, p and has a spin quantum number, I . • The nucleus has 2I+1 states, I, I-1, I-2, … -I • The spin quantum number, I, for 1 H, 13 C, 19 F, 31 P is ½, thus each nucleus has two spin states, I = ½, -½. • A spinning, charged nucleus creates a magnetic field. The magnetic moment, µ = γ p , where is magnetogyric ratio. For 1 H, = 2.6752 × 10 8 T -1 s -1 . • The magnetic moment and the nuclear spin have the same quantum states, I, I-1, I-2, … -I. • Two energy levels corresponding to the two magnetic moments for a nucleus with spin quantum number of ±1/2. • see Figure 19-1 and equations 19-3, to 19-5. 10 2 2 0 00 4 4 22 h EB h hB π υ + =− = ∆= = (frequency) The frequency of the transition between the two states is proportional to the applied magnetic field strength, B 0 .
Background image of page 4
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Distribution of particles between magnetic quantum states Thus: • For 1 H the number of nuclei in the lower state is only 33 ppm higher more than that in the higher state.
Background image of page 6
Image of page 7
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 05/15/2010 for the course CHEM 434 taught by Professor None during the Spring '07 term at University of Michigan-Dearborn.

Page1 / 24

lecture_14_Introduction and Application of NMR Spectroscopy...

This preview shows document pages 1 - 7. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online