A model for the quantitative analysis of silicon oxide using x-ray photoelectron spectroscopy (XPS) peak intensities is developed. This model is shown to have a precision of <5% in predicting the O/Si ratio within the XPS sampled volume. He+, Ne+, Ar+, and Xe+ bombardment of SiO2 are studied using this model. Results indicate that oxygen is preferentially depleted as a result of sputtering. Although elemental Si was not spectrally detected due to measurement noise and overlayer contamination, an equivalent upper limit to the elemental Si thickness of ∼2 Å is determined for Ne+, Ar+, and Xe+; He+ results in about 4 Å of elemental Si.