Finite Temperature String with Order Parameter as Collective Variables for Molecular Crystal: A Case of Polymorphic Transformation of TNT under External Electric Field.

An external electric field is an effective tool to induce the polymorphic transformation of molecular crystals, which is important practically in the chemical, material, and energy storage industries. However, the understanding of this mechanism is poor at the molecular level. In this work, two types of order parameters (OPs) were constructed for the molecular crystal based on the intermolecular distance, bond orientation, and molecular orientation.

[Identification and analysis of genuine and false Flos Rosae Rugosae by FTIR and 2D correlation IR spectroscopy].

The genuine and false Flos Rosae Rugosae (Flos Rosae Chinensis and Flos Rosa multiflora) were examined in terms of their differences by using Fourier transform infrared spectroscopy (FTIR) combined with two-dimensional (2D) correlation IR spectroscopy. The three species were shown very similar in FTIR spectra. The peak of 1318 cm(-1) of genuine Flos Rosae Rugosae is not obvious but this peak could be found sharp in Flos Rosae Chinensis and Flos Rosa multiflora.