In addition, both the atomic displacement parameters of the single-crystal diffraction data and the molecular dynamics-simulated mean squared displacements suggest the motions of the O and N atoms. Such weakening leads to an unusual negative thermal expansion along the c axis (-3%). O bonds revealed by the in situ FT-IR spectra.The weakening of hydrogen bond interactions in the HTP is also evidenced by the lower energy shift of the stretching vibration of the N-H

2SO4 undergoes a reversible phase transition (T c = 356 K) from the noncentrosymmetric room-temperature phase (P4̅21 c, RTP) to a centrosymmetric high-temperature phase (I4/mmm, HTP) where both the SO4 2- anions and + cations are highly disordered. Herein, we report a near-room-temperature nonlinear optical (NLO) switch material, 2SO4, exhibiting switching performance with strong room-temperature second harmonic generation (SHG) intensity that outperforms the UV-vis spectral region industry standard KH2PO4 (1.4 times stronger).

Chromatic displacement red giant