Cluster formation restricts dynamic nuclear polarization of xenon in solid mixtures

Publication: Research - peer-reviewJournal article – Annual report year: 2012

Standard

Cluster formation restricts dynamic nuclear polarization of xenon in solid mixtures. / Kuzma, N. N.; Pourfathi, M.; Kara, H.; Manasseh, P.; Ghosh, R. K.; Ardenkjaer-Larsen, J. H.; Kadlecek, S. J.; Rizi, R. R.

In: Journal of Chemical Physics, Vol. 137, No. 10, 2012.

Publication: Research - peer-reviewJournal article – Annual report year: 2012

Harvard

Kuzma, NN, Pourfathi, M, Kara, H, Manasseh, P, Ghosh, RK, Ardenkjaer-Larsen, JH, Kadlecek, SJ & Rizi, RR 2012, 'Cluster formation restricts dynamic nuclear polarization of xenon in solid mixtures' Journal of Chemical Physics, vol 137, no. 10., 10.1063/1.4751021

APA

Kuzma, N. N., Pourfathi, M., Kara, H., Manasseh, P., Ghosh, R. K., Ardenkjaer-Larsen, J. H., ... Rizi, R. R. (2012). Cluster formation restricts dynamic nuclear polarization of xenon in solid mixtures. Journal of Chemical Physics, 137(10). 10.1063/1.4751021

CBE

Kuzma NN, Pourfathi M, Kara H, Manasseh P, Ghosh RK, Ardenkjaer-Larsen JH, Kadlecek SJ, Rizi RR. 2012. Cluster formation restricts dynamic nuclear polarization of xenon in solid mixtures. Journal of Chemical Physics. 137(10). Available from: 10.1063/1.4751021

MLA

Vancouver

Author

Kuzma, N. N.; Pourfathi, M.; Kara, H.; Manasseh, P.; Ghosh, R. K.; Ardenkjaer-Larsen, J. H.; Kadlecek, S. J.; Rizi, R. R. / Cluster formation restricts dynamic nuclear polarization of xenon in solid mixtures.

In: Journal of Chemical Physics, Vol. 137, No. 10, 2012.

Publication: Research - peer-reviewJournal article – Annual report year: 2012

Bibtex

@article{1cfdcfd990d74481891da9537fc82420,
title = "Cluster formation restricts dynamic nuclear polarization of xenon in solid mixtures",
keywords = "PHYSICS,, HYPERPOLARIZED XE-129, EXCHANGE, STATE, NMR",
publisher = "American Institute of Physics",
author = "Kuzma, {N. N.} and M. Pourfathi and H. Kara and P. Manasseh and Ghosh, {R. K.} and Ardenkjaer-Larsen, {J. H.} and Kadlecek, {S. J.} and Rizi, {R. R.}",
year = "2012",
doi = "10.1063/1.4751021",
volume = "137",
number = "10",
journal = "Journal of Chemical Physics",
issn = "0021-9606",

}

RIS

TY - JOUR

T1 - Cluster formation restricts dynamic nuclear polarization of xenon in solid mixtures

A1 - Kuzma,N. N.

A1 - Pourfathi,M.

A1 - Kara,H.

A1 - Manasseh,P.

A1 - Ghosh,R. K.

A1 - Ardenkjaer-Larsen,J. H.

A1 - Kadlecek,S. J.

A1 - Rizi,R. R.

AU - Kuzma,N. N.

AU - Pourfathi,M.

AU - Kara,H.

AU - Manasseh,P.

AU - Ghosh,R. K.

AU - Ardenkjaer-Larsen,J. H.

AU - Kadlecek,S. J.

AU - Rizi,R. R.

PB - American Institute of Physics

PY - 2012

Y1 - 2012

N2 - During dynamic nuclear polarization (DNP) at 1.5 K and 5 T, Xe-129 nuclear magnetic resonance (NMR) spectra of a homogeneous xenon/1-propanol/trityl-radical solid mixture exhibit a single peak, broadened by H-1 neighbors. A second peak appears upon annealing for several hours at 125 K. Its characteristic width and chemical shift indicate the presence of spontaneously formed pure Xe clusters. Microwave irradiation at the appropriate frequencies can bring both peaks to either positive or negative polarization. The peculiar time evolution of Xe-129 polarization in pure Xe clusters during DNP can be modelled as an interplay of spin diffusion and T-1 relaxation. Our simple spherical-cluster model offers a sensitive tool to evaluate major DNP parameters in situ, revealing a severe spin-diffusion bottleneck at the cluster boundaries and a significant sample overheating due to microwave irradiation. Subsequent DNP system modifications designed to reduce the overheating resulted in four-fold increase of Xe-129 polarization, from 5.3% to 21%. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4751021]

AB - During dynamic nuclear polarization (DNP) at 1.5 K and 5 T, Xe-129 nuclear magnetic resonance (NMR) spectra of a homogeneous xenon/1-propanol/trityl-radical solid mixture exhibit a single peak, broadened by H-1 neighbors. A second peak appears upon annealing for several hours at 125 K. Its characteristic width and chemical shift indicate the presence of spontaneously formed pure Xe clusters. Microwave irradiation at the appropriate frequencies can bring both peaks to either positive or negative polarization. The peculiar time evolution of Xe-129 polarization in pure Xe clusters during DNP can be modelled as an interplay of spin diffusion and T-1 relaxation. Our simple spherical-cluster model offers a sensitive tool to evaluate major DNP parameters in situ, revealing a severe spin-diffusion bottleneck at the cluster boundaries and a significant sample overheating due to microwave irradiation. Subsequent DNP system modifications designed to reduce the overheating resulted in four-fold increase of Xe-129 polarization, from 5.3% to 21%. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4751021]

KW - PHYSICS,

KW - HYPERPOLARIZED XE-129

KW - EXCHANGE

KW - STATE

KW - NMR

U2 - 10.1063/1.4751021

DO - 10.1063/1.4751021

JO - Journal of Chemical Physics

JF - Journal of Chemical Physics

SN - 0021-9606

IS - 10

VL - 137

ER -