Premium
Complete spin dynamics of the AX, AX 2 and AX 3 spin systems. Application to BIRD pulses
Author(s) -
Bain Alex D.,
Burton Ian W.,
Carpenter Katharine A.,
Yang JiPing,
Reynolds William F.
Publication year - 1995
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.1260330309
Subject(s) - spins , pulse sequence , sequence (biology) , spin (aerodynamics) , pulse (music) , proton , ideal (ethics) , proton spin crisis , chemistry , physics , statistical physics , atomic physics , nuclear magnetic resonance , quantum mechanics , condensed matter physics , voltage , thermodynamics , biochemistry , philosophy , epistemology
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.