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Some "reflections" on the effects of finite gradient pulse lengths in PGSE NMR experiments in restricted systems

Price, W S and Söderman, Olle LU (2003) In Israel Journal of Chemistry 43(1-2). p.25-32
Abstract
It is generally difficult to analytically derive models describing the echo attenuation in pulsed gradient spin-echo (PGSE) experiments for even

he simplest porous systems that are commonly studied-especially when the gradient pulse (delta) is of finite length compared to the timescale of the diffusion measurement (Delta). Consequently, various levels of approximation are used to evaluate PGSE experiments. In the present paper, a conceptual view of q-space is given and two of the most common approximations, the short gradient pulse (SGP) and Gaussian phase distribution (GPD) approximations, are compared in detail with a recent matrix method, which provides "analytically" exact results giving a visual representation of the... (More)
It is generally difficult to analytically derive models describing the echo attenuation in pulsed gradient spin-echo (PGSE) experiments for even

he simplest porous systems that are commonly studied-especially when the gradient pulse (delta) is of finite length compared to the timescale of the diffusion measurement (Delta). Consequently, various levels of approximation are used to evaluate PGSE experiments. In the present paper, a conceptual view of q-space is given and two of the most common approximations, the short gradient pulse (SGP) and Gaussian phase distribution (GPD) approximations, are compared in detail with a recent matrix method, which provides "analytically" exact results giving a visual representation of the limitations of these approximations. The simulations are performed for diffusion between a pair of reflecting planes separated by a distance a. A modification that is sometimes applied to the short gradient pulse approximation in attempting to extend it to finite gradient pulses is also compared. The simulations reveal that, except when the experimental conditions closely match the requirements of the SGP and GPD simulati

ns, the matrix method must be used in order to correctly interpret the

data. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Israel Journal of Chemistry
volume
43
issue
1-2
pages
25 - 32
publisher
Weizmann science press
external identifiers
  • wos:000187990200004
  • scopus:16544367741
ISSN
0021-2148
DOI
10.1560/36L1-H74U-N33X-FY4D
language
English
LU publication?
yes
id
0f4d6962-0bc0-4a80-9138-bff9f8dcaabe (old id 122167)
date added to LUP
2007-07-12 10:35:06
date last changed
2018-01-07 09:15:47
@article{0f4d6962-0bc0-4a80-9138-bff9f8dcaabe,
  abstract     = {It is generally difficult to analytically derive models describing the echo attenuation in pulsed gradient spin-echo (PGSE) experiments for even <br/><br>
he simplest porous systems that are commonly studied-especially when the gradient pulse (delta) is of finite length compared to the timescale of the diffusion measurement (Delta). Consequently, various levels of approximation are used to evaluate PGSE experiments. In the present paper, a conceptual view of q-space is given and two of the most common approximations, the short gradient pulse (SGP) and Gaussian phase distribution (GPD) approximations, are compared in detail with a recent matrix method, which provides "analytically" exact results giving a visual representation of the limitations of these approximations. The simulations are performed for diffusion between a pair of reflecting planes separated by a distance a. A modification that is sometimes applied to the short gradient pulse approximation in attempting to extend it to finite gradient pulses is also compared. The simulations reveal that, except when the experimental conditions closely match the requirements of the SGP and GPD simulati<br/><br>
ns, the matrix method must be used in order to correctly interpret the<br/><br>
	data.},
  author       = {Price, W S and Söderman, Olle},
  issn         = {0021-2148},
  language     = {eng},
  number       = {1-2},
  pages        = {25--32},
  publisher    = {Weizmann science press},
  series       = {Israel Journal of Chemistry},
  title        = {Some "reflections" on the effects of finite gradient pulse lengths in PGSE NMR experiments in restricted systems},
  url          = {http://dx.doi.org/10.1560/36L1-H74U-N33X-FY4D},
  volume       = {43},
  year         = {2003},
}