𝔖 Bobbio Scriptorium
✦   LIBER   ✦

Complete spin dynamics of the AX, AX2 and AX3 spin systems. Application to BIRD pulses

✍ Scribed by Alex D. Bain; Ian W. Burton; Katharine A. Carpenter; Ji-Ping Yang; William F. Reynolds

Publisher
John Wiley and Sons
Year
1995
Tongue
English
Weight
863 KB
Volume
33
Category
Article
ISSN
0749-1581

No coin nor oath required. For personal study only.

✦ Synopsis

Abstract

The BIRD pulse sequence is widely used to distinguish between protons that are directly bonded to a ^13^C nucleus and those that are not. It consists of a proton 90° pulse, a delay of 1/(2^1^J~CH~), simultaneous carbon and proton 180° pulses, a further delay of 1/2__J__ and a final proton 90° pulse. For two spins at equilibrium, the effect of this sequence can be easily understood, but for complex systems the behaviour can be counter‐intuitive. This paper explains the general behaviour of the BIRD sequence using theoretical equations and numerical simulations, and discusses some practical applications of the BIRD pulse train. The theoretical equations are derived using tables of general behaviour for the spin systems AX, AX~2~ and AX~3~. The tables allow the exact calculation of the effect of any pulse sequence on these spin systems, including all multiple quantum effects. The simulations show that the sequence is usually robust with respect to pulse imperfections and non‐ideal spin systems. In other cases, particularly when signals should be suppressed, small errors can have dramatic consequences. The results derived here are for a BIRD sequence inserted into an INEPT experiment, but many of the conclusions can be applied to all of the more standard applications of the BIRD.

📜 SIMILAR VOLUMES

The theory of cosy NMR experiments revis
The theory of cosy NMR experiments revisited: Application to an AX spin system of quadrupolar nuclei
✍ P. Kempgens 📂 Article 📅 2010 🏛 John Wiley and Sons 🌐 English ⚖ 295 KB

## Abstract The two‐dimensional nuclear magnetic resonance correlation spectroscopy (2D NMR COSY) spectrum of an AX spin system of spin‐1 has been calculated by numerical density matrix calculations. The mathematical expressions found are valid for an AX spin system of any spins. These expressions

Ab Initio Studies of the [AX]2 Spin Syst
Ab Initio Studies of the [AX]2 Spin Systems of cis- and trans-N2F2
✍ Michał Jaszuński; Trygve Helgaker; Kenneth Ruud 📂 Article 📅 1996 🏛 John Wiley and Sons 🌐 English ⚖ 394 KB 👁 2 views

Ab initio calculations of all indirect spin-spin coupling constants in the cis and tvans isomers of N,F, are discussed. The accuracy of the theoretical results is estimated and their values are compared with recent experimental data. Ab initio calculated values can be helpful in the analysis of the

Spin-1 Double Quantum Spectroscopy in th
Spin-1 Double Quantum Spectroscopy in the Isotropic Phase: INADEQUATE Spectra of 2H,2H and 6Li,6Li AX Spin Systems
✍ Narayanan Chandrakumar; Hans-Egbert Mons; Dietmar Hüls; Harald Günther 📂 Article 📅 1996 🏛 John Wiley and Sons 🌐 English ⚖ 323 KB 👁 1 views

A density matrix treatment is presented which describes the main features of INADEQUATE experiments for spin-1 AX spin systems. It is shown that apart from two-spin double quantum peaks, which carry correlation information, one-spin double quantum peaks are to be expected. In the latter, homoculear

The 15N-isotopomers of cis- and trans-di
The 15N-isotopomers of cis- and trans-difluorodiazine; A 19F NMR investigation of the two [AX]2 spin systems of 15N2F2
✍ F. Aubke; G. Hägele; H. Willner 📂 Article 📅 1995 🏛 John Wiley and Sons 🌐 English ⚖ 344 KB 👁 1 views

## Abstract The decomposition of ^15^N~3~F at −20°C leads to __cis__‐ and __trans__‐^15^N~2~F~2~. The corresponding ^19^F NMR spectra were analysed as [AX]~2~ systems. ^19^F, ^15^N and ^14^N NMR spectra were simulated using the novel PC program systems DSYMPCD, DCYMPCD and WIN‐DAISY running under W