Thermal averaging of the spin-rotation coupling in small molecules leads to an isotropic NMR shielding

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

It has been known for over 70 years that nuclear spins couple to molecular rotation via a Zeeman interaction. This spin-rotation coupling can be observed as a discrete splitting in molecular beam magnetic resonance experiments, but is quenched by molecular collisions at higher pressures. We show that because of differential thermal population of M J levels at high magnetic fields, the spin rotation coupling retains a small isotropic component at high field. For all but the smallest molecules at very low temperature, the residual coupling is temperature independent and linear in the magnetic field; it therefore closely mimics the chemical shift. The 'super spin rotation' shift may in the future be a necessary correction to ultra - high precision computations of the NMR chemical shielding of small molecules in gases and liquids.

Original languageEnglish (US)
Pages (from-to)299-303
Number of pages5
JournalJournal of Magnetic Resonance
Volume212
Issue number2
DOIs
StatePublished - Oct 1 2011

Fingerprint

Shielding
shielding
Hot Temperature
Nuclear magnetic resonance
nuclear magnetic resonance
Molecules
Magnetic Fields
molecules
molecular collisions
molecular rotation
Magnetic fields
magnetic fields
nuclear spin
molecular beams
Temperature
Molecular beams
chemical equilibrium
magnetic resonance
Chemical shift
Magnetic resonance

Keywords

  • Chemical shielding
  • Gases
  • Molecular g factor
  • NMR
  • Spin-rotation

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Nuclear and High Energy Physics
  • Condensed Matter Physics

Cite this

Thermal averaging of the spin-rotation coupling in small molecules leads to an isotropic NMR shielding. / Harbison, Gerard S.

In: Journal of Magnetic Resonance, Vol. 212, No. 2, 01.10.2011, p. 299-303.

Research output: Contribution to journalArticle

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