TY - JOUR
T1 - Two-dimensional Nutation Echo Nuclear Quadrupole Resonance Spectroscopy
AU - Harbison, Gerard S.
AU - Slokenbergs, Andris
N1 - Funding Information:
Acknowledgement is made to the Donors of the Petroleum Research Fund, grant number 19107G7, for partial support of this research. Support was also obtained from the National Institutes of Health (GM-39071) and the National Science Foundation Materials Research Initiative (DMR-8706432). We thank Dr. Thomas M. Barbara for ever-helpful discussions, and Professor M. Goldman for sending us a preprint of his paper prior to publication.
PY - 1990/4/1
Y1 - 1990/4/1
N2 - We discuss two new two-dimensional nuclear quadrupole resonance experiments, both based on the principle of nutation spectroscopy, which can be used to determine the asymmetry parameter, and thus the full quadrupolar tensor, of spin-3/2 nuclei at zero applied magnetic field. The first experiment is a simple nutation pulse sequence in which the first time period (t1) is the duration of the radiofrequency exciting pulse; and the second (t2) is the normal free-precession of a quadrupolar nucleus at zero-field. After double Fourier-transformation, the result is a 2 D spectrum in which the first frequency dimension is the nutation spectrum for the quadrupolar nucleus at zero-field. For polycrystalline samples this sequence generates powder lineshapes; the position of the singularities, in these lineshapes can be used to determine the asymmetry parameters n in a very straightforward manner, n has previously only been obtainable using Zeeman perturbed NQR methods. The second sequence is the same nutation experiment with a spin-echo pulse added. The virtue of this refocussing pulse is that it allows acquisition of nutation spectra from samples with arbitrary inhomogeneous linewidth; thus, asymmetry parameters can be determined even where the quadrupolar resonance is wider than the bandwidth of the spectrometer. Experimental examples of 35Cl, 81Br and 63Cu nutation and nutation-echo spectra are presented.
AB - We discuss two new two-dimensional nuclear quadrupole resonance experiments, both based on the principle of nutation spectroscopy, which can be used to determine the asymmetry parameter, and thus the full quadrupolar tensor, of spin-3/2 nuclei at zero applied magnetic field. The first experiment is a simple nutation pulse sequence in which the first time period (t1) is the duration of the radiofrequency exciting pulse; and the second (t2) is the normal free-precession of a quadrupolar nucleus at zero-field. After double Fourier-transformation, the result is a 2 D spectrum in which the first frequency dimension is the nutation spectrum for the quadrupolar nucleus at zero-field. For polycrystalline samples this sequence generates powder lineshapes; the position of the singularities, in these lineshapes can be used to determine the asymmetry parameters n in a very straightforward manner, n has previously only been obtainable using Zeeman perturbed NQR methods. The second sequence is the same nutation experiment with a spin-echo pulse added. The virtue of this refocussing pulse is that it allows acquisition of nutation spectra from samples with arbitrary inhomogeneous linewidth; thus, asymmetry parameters can be determined even where the quadrupolar resonance is wider than the bandwidth of the spectrometer. Experimental examples of 35Cl, 81Br and 63Cu nutation and nutation-echo spectra are presented.
UR - http://www.scopus.com/inward/record.url?scp=4243116963&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=4243116963&partnerID=8YFLogxK
U2 - 10.1515/zna-1990-3-464
DO - 10.1515/zna-1990-3-464
M3 - Article
AN - SCOPUS:4243116963
VL - 45
SP - 575
EP - 580
JO - Zeitschrift fur Naturforschung - Section A Journal of Physical Sciences
JF - Zeitschrift fur Naturforschung - Section A Journal of Physical Sciences
SN - 0932-0784
IS - 3-4
ER -