Core Binding Energy Difference between Bridging and Nonbridging Oxygen Atoms in a Silicate Chain

Area of Science:

• Mineralogy
• Geochemistry
• Materials Science

Background:

• Olivines and pyroxenes are essential rock-forming silicate minerals.
• Understanding their atomic structure is crucial for geological and materials science applications.
• X-ray photoelectron spectroscopy (XPS) is a surface-sensitive technique for elemental and chemical state analysis.

Purpose of the Study:

• To differentiate between olivine and pyroxene structures using oxygen 1s X-ray photoelectron spectra.
• To investigate the chemical environment of oxygen atoms in pyroxene silicate chains.

Main Methods:

• Analysis of X-ray photoelectron spectra (XPS) focusing on the oxygen 1s core-level.
• Comparison of spectral components and intensity ratios between olivine and pyroxene samples.

Main Results:

• Olivine oxygen 1s spectra exhibited a single spectral component.
• Pyroxene oxygen 1s spectra displayed two distinct components.
• The two components in pyroxene spectra had an intensity ratio of approximately 2:1 and an energy separation of about 1 eV.

Conclusions:

• The observed spectral differences are attributed to the distinct bonding environments of oxygen atoms in olivine and pyroxene.
• The two components in pyroxene spectra are interpreted as arising from nonbridging and bridging oxygen atoms within the silicate chain structure.