Multifrequency EPR spectra of molecular oxygen in solid Air

Area of Science:

• Spectroscopy
• Solid-state physics
• Quantum chemistry

Background:

• Electron paramagnetic resonance (EPR) is a powerful technique for studying paramagnetic species.
• Molecular oxygen (O2) is a common paramagnetic impurity in various samples, including solid air.
• High-field and high-frequency EPR offer enhanced resolution and sensitivity for spectral analysis.

Purpose of the Study:

• To characterize the multifrequency EPR spectra of molecular oxygen in solid air.
• To determine the spin Hamiltonian parameters for O2 in this condensed phase.
• To assess the relevance of these findings for high-field EPR applications.

Main Methods:

• Multifrequency EPR spectroscopy was conducted on solid air samples.
• Measurements were performed in the 94 to 550 GHz frequency range.
• Data were analyzed using the spin Hamiltonian model.

Main Results:

• Axial S = 1 spectra characteristic of molecular oxygen were observed.
• A zero-field splitting parameter D = 3.572(3) cm(-1) was determined for O2.
• The results provide a detailed spectral signature for O2 in solid air.

Conclusions:

• The study successfully characterized the EPR spectra of molecular oxygen in solid air.
• The determined spin Hamiltonian parameters are crucial for interpreting EPR data where O2 is present.
• This research contributes to the application of high-field EPR for analyzing paramagnetic impurities.