Acoustic Shock‐Wave‐Induced Crystallographically Order–Disorder Switchable Phase Transition of Ammonium Sulfate Crystal: X‐Ray Diffraction and Raman Spectroscopic Approach

Abstract

In this framework, the authors have intended to examine the phase‐transition probability of ammonium sulfate (NH4)2SO4 under dynamic shock loaded conditions, whereby it is authenticated from the observations that the title crystal undergoes the process of reversible phase transition of crystallographic nature. The observed phase‐transition sequence is Pnam (crystalline) → Pnam (crystalline) → distorted Pnam (semicrystalline) → Pnam (crystalline) → Pnam (crystalline) under the exposure of 0, 1, 2, 3, and 4 shocks, respectively, such that the order of the transition is evaluated by diffraction and spectroscopic techniques. The obtained differential scanning calorimetry and thermogravimetric analysis results provide the crystalline‐state ammonium sulfate which has higher thermal stability than that of the disordered‐state ammonium sulfate. Analyzing the acquired results of the analytical experiments, the authentication can be arrived at such that the phase transition of reversible nature is enforced by the molecular distortions followed by the occurrence of rotational disorder involving ammonium and sulfate groups of ions influenced by the impulsion of shock waves thereby the title crystal can be a potential material for molecular switching applications.