Calibration of local chemical pressure by optical probe.

Chemical stabilization of a high-pressure metastable state is a major challenge for the development of advanced materials. Although chemical pressure () can effectively simulate the effect of physical pressure (), experimental calibration of the pressure passed to local structural motifs, denoted as local chemical pressure () which significantly governs the function of solid materials, remains absent due to the challenge of probing techniques. Here we establish an innovative methodology to experimentally calibrate the and build a bridge between and via an optical probe strategy. Site-selective Bi-traced VO ( = Y, Gd) is adopted as a prototype to introduce Bi optical probes and on-site sense of the experienced by the O motif. The cell compression of BiVO under is chemically simulated by smaller-ion substitution (Sc → ) in ScBiVO. The consistent red shift () of the emission spectra of Bi, which is dominated by locally pressure-induced O dodecahedral variation in BiVO () and ScBiVO (), respectively, is evidence of their similar pressure-dependent local structure evolution. This innovative -based experimental calibration of in the crystal-field dimension portrays the anisotropic transmission of to the local structure and builds a bridge between and to guide a new perspective for affordable and practical interception of metastable states.