Pressure tuning of spectral holes in organic crystalline materials: irreversible effects

The behavior of spectral holes under pressure in a polycrystalline material, namely dimethyl-s-tetrazine (DMST) doped n-octane was investigated and compared with the behavior in a durene single crystal host and glasses. Application of pressure induces frequency shifts and line broadenings which are significantly larger than in single crystals and glasses. Part of the broadening is irreversible and is attributed to the creation of dipolar strain fields. The distribution of dislocation thresholds is continuous with no obvious lower cut off. The response of the material to pressure changes depends on its history.