Singlet excitation in the intermediate magnetic equivalence regime and field-dependent study of singlet-triplet leakage

Boris Kharkov, Xueyou Duan, Emily S. Tovar, James Canary, Alexej Jerschow

Research output: Contribution to journalArticle

Abstract

The examination and optimized preparation of nuclear spin singlet order has enabled the development of new types of applications that rely on potentially long-term polarization storage. Lifetimes several orders of magnitude longer than T1 have been observed. The efficient creation of such states relies on special pulse sequences. The extreme cases of very large and very small magnetic equivalence received primary attention, while relatively little effort has been directed towards studying singlet relaxation in the intermediate regime. The intermediate case is of interest as it is relevant for many spin systems, and would also apply to heteronuclear systems in very low magnetic fields. Experimental evidence for singlet-triplet leakage in the intermediate regime is sparse. Here we describe a pulse sequence for efficiently creating singlets in the intermediate regime in a broad-band fashion. Singlet lifetimes are studied with a specially synthesized molecule over a wide range of magnetic fields using a home-built sample-lift apparatus. The experimental results are supplemented with spin simulations using parameters obtained from ab initio calculations. This work indicates that the chemical shift anisotropy (CSA) mechanism is relatively weak compared to singlet-triplet leakage for the proton system observed over a large magnetic field range. These experiments provide a mechanism for expanding the scope of singlet NMR to a larger class of molecules, and provide new insights into singlet lifetime limiting factors.

Original languageEnglish (US)
Pages (from-to)2595-2600
Number of pages6
JournalPhysical Chemistry Chemical Physics
Volume21
Issue number5
DOIs
StatePublished - Jan 1 2019

Fingerprint

equivalence
leakage
Magnetic fields
life (durability)
magnetic fields
excitation
Molecules
Chemical shift
pulses
nuclear spin
chemical equilibrium
Protons
molecules
Anisotropy
examination
Nuclear magnetic resonance
Polarization
broadband
preparation
nuclear magnetic resonance

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

Cite this

Singlet excitation in the intermediate magnetic equivalence regime and field-dependent study of singlet-triplet leakage. / Kharkov, Boris; Duan, Xueyou; Tovar, Emily S.; Canary, James; Jerschow, Alexej.

In: Physical Chemistry Chemical Physics, Vol. 21, No. 5, 01.01.2019, p. 2595-2600.

Research output: Contribution to journalArticle

@article{b82693f9e3f44925a9d96cd6337a9d07,
title = "Singlet excitation in the intermediate magnetic equivalence regime and field-dependent study of singlet-triplet leakage",
abstract = "The examination and optimized preparation of nuclear spin singlet order has enabled the development of new types of applications that rely on potentially long-term polarization storage. Lifetimes several orders of magnitude longer than T1 have been observed. The efficient creation of such states relies on special pulse sequences. The extreme cases of very large and very small magnetic equivalence received primary attention, while relatively little effort has been directed towards studying singlet relaxation in the intermediate regime. The intermediate case is of interest as it is relevant for many spin systems, and would also apply to heteronuclear systems in very low magnetic fields. Experimental evidence for singlet-triplet leakage in the intermediate regime is sparse. Here we describe a pulse sequence for efficiently creating singlets in the intermediate regime in a broad-band fashion. Singlet lifetimes are studied with a specially synthesized molecule over a wide range of magnetic fields using a home-built sample-lift apparatus. The experimental results are supplemented with spin simulations using parameters obtained from ab initio calculations. This work indicates that the chemical shift anisotropy (CSA) mechanism is relatively weak compared to singlet-triplet leakage for the proton system observed over a large magnetic field range. These experiments provide a mechanism for expanding the scope of singlet NMR to a larger class of molecules, and provide new insights into singlet lifetime limiting factors.",
author = "Boris Kharkov and Xueyou Duan and Tovar, {Emily S.} and James Canary and Alexej Jerschow",
year = "2019",
month = "1",
day = "1",
doi = "10.1039/c8cp06883f",
language = "English (US)",
volume = "21",
pages = "2595--2600",
journal = "Physical Chemistry Chemical Physics",
issn = "1463-9076",
publisher = "Royal Society of Chemistry",
number = "5",

}

TY - JOUR

T1 - Singlet excitation in the intermediate magnetic equivalence regime and field-dependent study of singlet-triplet leakage

AU - Kharkov, Boris

AU - Duan, Xueyou

AU - Tovar, Emily S.

AU - Canary, James

AU - Jerschow, Alexej

PY - 2019/1/1

Y1 - 2019/1/1

N2 - The examination and optimized preparation of nuclear spin singlet order has enabled the development of new types of applications that rely on potentially long-term polarization storage. Lifetimes several orders of magnitude longer than T1 have been observed. The efficient creation of such states relies on special pulse sequences. The extreme cases of very large and very small magnetic equivalence received primary attention, while relatively little effort has been directed towards studying singlet relaxation in the intermediate regime. The intermediate case is of interest as it is relevant for many spin systems, and would also apply to heteronuclear systems in very low magnetic fields. Experimental evidence for singlet-triplet leakage in the intermediate regime is sparse. Here we describe a pulse sequence for efficiently creating singlets in the intermediate regime in a broad-band fashion. Singlet lifetimes are studied with a specially synthesized molecule over a wide range of magnetic fields using a home-built sample-lift apparatus. The experimental results are supplemented with spin simulations using parameters obtained from ab initio calculations. This work indicates that the chemical shift anisotropy (CSA) mechanism is relatively weak compared to singlet-triplet leakage for the proton system observed over a large magnetic field range. These experiments provide a mechanism for expanding the scope of singlet NMR to a larger class of molecules, and provide new insights into singlet lifetime limiting factors.

AB - The examination and optimized preparation of nuclear spin singlet order has enabled the development of new types of applications that rely on potentially long-term polarization storage. Lifetimes several orders of magnitude longer than T1 have been observed. The efficient creation of such states relies on special pulse sequences. The extreme cases of very large and very small magnetic equivalence received primary attention, while relatively little effort has been directed towards studying singlet relaxation in the intermediate regime. The intermediate case is of interest as it is relevant for many spin systems, and would also apply to heteronuclear systems in very low magnetic fields. Experimental evidence for singlet-triplet leakage in the intermediate regime is sparse. Here we describe a pulse sequence for efficiently creating singlets in the intermediate regime in a broad-band fashion. Singlet lifetimes are studied with a specially synthesized molecule over a wide range of magnetic fields using a home-built sample-lift apparatus. The experimental results are supplemented with spin simulations using parameters obtained from ab initio calculations. This work indicates that the chemical shift anisotropy (CSA) mechanism is relatively weak compared to singlet-triplet leakage for the proton system observed over a large magnetic field range. These experiments provide a mechanism for expanding the scope of singlet NMR to a larger class of molecules, and provide new insights into singlet lifetime limiting factors.

UR - http://www.scopus.com/inward/record.url?scp=85060775910&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85060775910&partnerID=8YFLogxK

U2 - 10.1039/c8cp06883f

DO - 10.1039/c8cp06883f

M3 - Article

VL - 21

SP - 2595

EP - 2600

JO - Physical Chemistry Chemical Physics

JF - Physical Chemistry Chemical Physics

SN - 1463-9076

IS - 5

ER -