Measurement of quadrupolar coupling constants, shielding tensor elements, and the relative orientation of quadrupolar and shielding tensor principal axis systems for rubidium-87 and rubidium-85 nuclei in rubidium salts by solid-state nuclear magnetic resonance

• Published in: Journal of physical chemistry (1952) Vol. 94; no. 2; pp. 553 - 561
• Main Authors: CHENG, J. T, EDWARDS, J. C, ELLIS, P. D
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 25.01.1990
• Subjects: ALKALI METAL ISOTOPES; Atomic and molecular physics; BETA DECAY RADIOISOTOPES; BETA-MINUS DECAY RADIOISOTOPES; CATALYSTS; COMPUTERIZED SIMULATION; COUPLING CONSTANTS; DATA; DATA ANALYSIS; Exact sciences and technology; EXPERIMENTAL DATA; INFORMATION; INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; INTERMEDIATE MASS NUCLEI; ISOMERIC TRANSITION ISOTOPES; ISOTOPES; MEASURING INSTRUMENTS; MEASURING METHODS; Molecular properties and interactions with photons; NMR SPECTRA; Nuclear resonance and relaxation; NUCLEI; NUMERICAL DATA; ODD-EVEN NUCLEI; Physics; RADIOISOTOPES; RUBIDIUM 85; RUBIDIUM 87; RUBIDIUM ISOTOPES; SIMULATION; SPECTRA; STABLE ISOTOPES; TENSOR FORCES; YEARS LIVING RADIOISOTOPES 400201 > Chemical & Physicochemical Properties; Spin lattice relaxation; NMR spectrometry; Experimental study; Quadrupolar interaction; Relaxation time; Inorganic compound; Solid state; Dipolar interaction; Quadrupole coupling constant; Simulation; Spectral line profile; Rubidium Compounds; Hydrates
• ISSN: 0022-3654; 1541-5740
• DOI: 10.1021/j100365a014

The spin lattice relaxation time, T{sub 1}, quadrupolar coupling constant, Q{sub cc}, and chemical shielding tensor elements of several rubidium salts have been surveyed at the frequency 130.88 MHz for {sup 87}Rb and 38.64 MHz for {sup 85}Rb, i.e. 9.4T, or 400 MHz for {sup 1}h's. Typical relaxation times for {sup 87}Rb are in the range of 100-300 ms and 50-300 ms for {sup 85}Rb. The Q{sub cc} values are in the range of 7-14 MHz for {sup 85}Rb and 3-11 MHz for {sup 87}Rb. A program was created to numerically simulate and fit experimental powder patterns for the {plus minus} 1/2 central transition, where the principal axis systems (PAS) of the shielding and quadrupole tensors are not coincident. The analysis shows that having both nuclides available with significantly different quadrupole coupling constants makes the general line-shape problem more tractable. That is, the {sup 85}Rb data provides an excellent visualization of chemically different rubidium atoms when there are significant differences in the value of Q{sub cc}. Such data would be difficult to extract from the corresponding {sup 87}Rb line shapes due to the smaller value of Q{sub cc}. The {sup 87}Rb nuclide, however, because of its smaller value of Q{sub cc}, provides an excellent opportunity to observe the consequences of the noncoincident PAS frames between the shielding and quadrupole tensors.