Lecture

Quantum Description of Pulsed NMR

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In course

CH-401: Advanced nuclear magnetic resonance

Principles of Magnetic Resonance Imaging (MRI) and applications to medical imaging. Principles of modern multi-dimensional NMR in liquids and solids. Structure determination of proteins & materials. Measurement of molecular dynamics. Principles of Hyperpol ...

Description

This lecture covers the principles of Pulsed NMR Spectroscopy, including the Zeeman interaction, chemical shift, scalar coupling, and dipolar coupling. It delves into the quantum mechanics behind nuclear magnetic moments, bulk magnetization, and the rotating frame. The presentation explores the dynamics of transverse magnetization, resonant pulses, and the manipulation of spins through radiofrequency irradiation. It discusses the density operator, the Schrodinger equation of motion, and the Liouville-von Neumann equation. The lecture concludes with insights on the effective fields in the rotating frame, resonant pulses, and the detection of NMR signals.

Instructor

David Lyndon Emsley

Current Work Our research centres on the development of new NMR spectroscopy experiments to determine the atomic-level structure and dynamics of complex materials and molecular systems, to solve a range of problems across disciplines. Teaching & PhD PhD Students Ray Cowen, Ümmügülsüm Günes, Máté Visegrádi, Ruben Rodriguez Madrid Past EPFL PhD Students Dominik Józef Kubicki, Arthur César Pinon, Albert Hofstetter, Federico Maria Paruzzo, Baptiste Busi, Snaedis Björgvinsdóttir, Martins Balodis, Aditya Mishra

Official source

Ontological neighbourhood

Physics

Condensed matter physics: Phase transitions

Chemistry

Physical chemistry: Spectroscopy

Related concepts (32)

Nuclear magnetic resonance spectroscopy

Nuclear magnetic resonance spectroscopy, most commonly known as NMR spectroscopy or magnetic resonance spectroscopy (MRS), is a spectroscopic technique to observe local magnetic fields around atomic nuclei. This spectroscopy is based on the measurement of absorption of electromagnetic radiations in the radio frequency region from roughly 4 to 900 MHz. Absorption of radio waves in the presence of magnetic field is accompanied by a special type of nuclear transition, and for this reason, such type of spectroscopy is known as Nuclear Magnetic Resonance Spectroscopy.

Spin echo

In magnetic resonance, a spin echo or Hahn echo is the refocusing of spin magnetisation by a pulse of resonant electromagnetic radiation. Modern nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) make use of this effect. The NMR signal observed following an initial excitation pulse decays with time due to both spin relaxation and any inhomogeneous effects which cause spins in the sample to precess at different rates. The first of these, relaxation, leads to an irreversible loss of magnetisation.

Two-dimensional nuclear magnetic resonance spectroscopy

Two-dimensional nuclear magnetic resonance spectroscopy (2D NMR) is a set of nuclear magnetic resonance spectroscopy (NMR) methods which give data plotted in a space defined by two frequency axes rather than one. Types of 2D NMR include correlation spectroscopy (COSY), J-spectroscopy, exchange spectroscopy (EXSY), and nuclear Overhauser effect spectroscopy (NOESY). Two-dimensional NMR spectra provide more information about a molecule than one-dimensional NMR spectra and are especially useful in determining the structure of a molecule, particularly for molecules that are too complicated to work with using one-dimensional NMR.

J-coupling

In nuclear chemistry and nuclear physics, J-couplings (also called spin-spin coupling or indirect dipole–dipole coupling) are mediated through chemical bonds connecting two spins. It is an indirect interaction between two nuclear spins that arises from hyperfine interactions between the nuclei and local electrons. In NMR spectroscopy, J-coupling contains information about relative bond distances and angles. Most importantly, J-coupling provides information on the connectivity of chemical bonds.

Schrödinger equation

The Schrödinger equation is a linear partial differential equation that governs the wave function of a quantum-mechanical system. Its discovery was a significant landmark in the development of quantum mechanics. The equation is named after Erwin Schrödinger, who postulated the equation in 1925 and published it in 1926, forming the basis for the work that resulted in his Nobel Prize in Physics in 1933. Conceptually, the Schrödinger equation is the quantum counterpart of Newton's second law in classical mechanics.

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