Comment on pressure dependence of wall relaxation in polarized 3He gaseous cells

Zheng et al. [Zheng, Gao, Ye, and Zhang, Phys. Rev. A 83, 061401(R) (2011)] have measured a strong linear pressure dependence of the nuclear relaxation rate of 3He in glass cells typically used to generate and/or store polarized 3He at room and cryogenic temperatures. Their interpretation is that this linear dependence is a general characteristic of paramagnetic wall relaxation, and they offer a theoretical explanation of the effect based on diffusion theory in the bulk with an incorrect boundary condition.We question the physical basis of the boundary condition and suggest some alternate explanations of the observations. Numerous previous studies support a broadly valid pressure-independent model for wall relaxation.