Quadrupole parameters of 11B in crystalline CaO.B2O3

Area of Science:

• Solid-state Chemistry
• Materials Science
• Nuclear Magnetic Resonance Spectroscopy
• Nuclear Quadrupole Resonance Spectroscopy

Background:

• Borate glasses and crystals are crucial in various technological applications.
• Accurate characterization of local atomic environments is essential for understanding material properties.
• Previous measurements of 11B parameters in CaO.B2O3 lacked the desired precision.

Purpose of the Study:

• To precisely determine the quadrupole coupling constant (Qcc) and asymmetry parameter (eta) for 11B in crystalline CaO.B2O3.
• To compare the accuracy of different NQR and NMR methodologies for characterizing 11B.
• To provide highly accurate spectroscopic data for theoretical and experimental validation.

Main Methods:

• Utilized three distinct Nuclear Quadrupole Resonance (NQR) and Nuclear Magnetic Resonance (NMR) techniques.
• Methods included: 11B and 10B NQR, combined 11B NQR and NMR, and 11B Zeeman NQR powder pattern analysis.
• Measurements were conducted at both 77 K and 300 K.

Main Results:

• Determined highly accurate Qcc and eta values for 11B in crystalline CaO.B2O3 at 77 K (Qcc = 2594.3 ± 0.5 kHz, eta = 0.515 ± 0.001) and 300 K (Qcc = 2573.5 ± 0.5 kHz, eta = 0.511 ± 0.002).
• These results demonstrate superior accuracy compared to previous methods, including analysis of second-order quadrupolar effects in 11B NMR spectra.
• The precision achieved validates the employed NQR and NMR techniques for detailed solid-state analysis.

Conclusions:

• The study successfully established highly precise quadrupole interaction parameters for 11B in crystalline CaO.B2O3.
• The employed NQR and NMR methods offer enhanced accuracy for characterizing boron sites in solid materials.
• The precise data obtained can serve as a benchmark for theoretical calculations and further material investigations.