We performed Raman and infrared (IR) spectroscopy measurements of hydrogen at 295 K up to 280 GPa at an IR synchrotron facility of SSRF. To reach the highest pressure, hydrogen was loaded into toroidal diamond anvils with 40 micrometers central culet. The intermolecular coupling has been determined by concomitant measurements of the IR and Raman vibron modes. In phase IV, we find that the intermolecular coupling is much stronger in the graphene (G) like layer of elongated molecules compared to the Br2 like layer of shortened molecules and it increases with pressure much faster in the G layer compared to the Br2 layer. These heterogeneous lattice dynamical properties are unique features of highly fluxional hydrogen phase IV.
The esoteric importance of intermolecular hydrogen bonding interaction to design novel methylammonium trihalide organic-inorganic hybrid perovskite solar cell materials is uncovered, establishing the unified structure-property relationship between the calculated Y...H intermolecular hydrogen bonding distance and the experimentally reported onset of optical absorption (bandgap) for the bulk geometries of the ten-membered methylammonium lead trihalide (CH3NH3PbY3) perovskite solar cell series, where Y = X (X = Cl, Br, I) and the mixed halogen derivatives. The same relationship is also revealed f…
The local intermolecular structure and related dynamics in the liquid cis-trans N-methylformamide mixture at ambient temperature and density conditions have been systematically studied by employing Born-Oppenheimer molecular dynamics simulation techniques. Particular attention has been paid to the local structure around the cis- and trans- conformers and the formation and dynamics of hydrogen bonds with their closest neighbors. The calculated atom-atom radial distribution functions are in very good agreement with available experimental data and reveal the existence of different types of hydrog…
We have carried out a density functional theory study on the structures of DMSO clusters and analysed the structure and their stability using molecular electrostatic potential and quantum theory of atoms-in-molecules (QTAIM). The ground state geometry of the DMSO clusters, prefer to exist in ouroboros shape. Pair wise interaction energy calculation show the interaction between methyl groups of adjacent DMSO molecules and a destabilization is is created by the methyl groups which are away from each other. Molecular electrostatic potential analysis shows the existence of hole on the odd numbered…
Ammonium DiNitramide (ADN) is one of the most promising green energetic oxidizers for future rocket propellant formulations. In the present work, we report a detailed theoretical study on structural, elastic, and vibrational properties of the emerging oxidizer under hydrostatic compression using various dispersion correction methods to capture weak intermolecular (van der Waals and hydrogen bonding) interactions. The calculated ground state lattice parameters, axial compressibilities, and equation of state are in good accord with the available experimental results. Strength of intermolecular i…
The laws of quantum mechanics are often tested against the behaviour of the lightest element in the periodic table, hydrogen. One of the most striking properties of molecular hydrogen is the coupling between molecular rotational properties and nuclear spin orientations, giving rise to the spin isomers ortho- and para-hydrogen. At high pressure, as intermolecular interactions increase significantly, the free rotation of H2 molecules is increasingly hindered, and consequently a modification of the coupling between molecular rotational properties and the nuclear spin system can be anticipated. To…
Theoretical analysis of the effect of an external vibration on proton transfer (PT) in a hydrogen bond (HB) is carried out. It is based on the two-dimensional Schrödinger equation with trigonometric double-well potential. Its solution obtained within the framework of the standard adiabatic approximation is available. An analytic formula is derived that provides the calculation of PT rate with the help of elements implemented in {\sl {Mathematica}}. We exemplify the general theory by calculating PT rate constant for the intermolecular HB in the Zundel ion ${\rm{H_5O_2^{+}}}$ (oxonium hydrate). …
Enhanced reversible barocaloric effect at low pressure in neopentyl plastic crystal solid solutions
University of Glasgow（格拉斯哥大学）；University of Cambridge（剑桥大学）；Institut Laue Langevin（朗之万研究所）；Universitat Politecnica de Catalunya（加泰罗尼亚理工大学）；Diamond Light Source（钻石光源）
