A theoretical study of the liquid structure of nitromethane with RISM method

Abstract

An integral equation theory for molecular liquids, reference interaction site model (RISM), was applied to understand the liquid structure of nitromethane, which is extensively used as a solvent. In the theory, liquid structure is described by a set of pair correlation functions. With the aid of ab initio molecular orbital calculations, representative peaks were able to be related to specific configurations of molecules.

Theoretical gas to liquid shift of 15N isotropic nuclear magnetic shielding in nitromethane using ab initio molecular dynamics and GIAO/GIPAW calculations

“…This is usually verified by examining the radial distribution function g(r) of characteristic interatomic distances, in comparison with experimental data. When considering nitromethane liquid simulations under periodic boundary conditions, a good agreement is obtained with previous MD and experiments [39][40][41][42] even if our density is slightly smaller than the experimental one (1.11 and 1.14 g cm À3 , respectively). Indeed all principal features that characterize g(r) functions are well reproduced by simulations (Fig.…”

“…When considering nitromethane liquid simulations under periodic boundary conditions, a good agreement is obtained with previous MD and experiments [39][40][41][42] even if our density is slightly smaller than the experimental one (1.11 and 1.14 g cm À3 , respectively). If one wants to mimic the liquid phase, a single cluster configuration is definitely not sufficient.…”

Water as a solute in nitromethane: Effect of H2O–D2O isotope substitution on the solution volumetric properties between 278.15K and 318.15K

“…The water-containing molecular aggregates with deuterium-bonding are stronger than the structure entities (''solvate complexes") formed due to H-bonding, although, as a whole, the stability of both aggregates is to be lower than that in the structural matrices of ordinary and heavy water. Certainly, the packing (steric) factor caused by a volume alteration due to threefold difference in V i between H 2 O (D 2 O) and NM, as well as a complex character of the spatial configuration of a solvent molecule [36,72], cannot be fully disregarded when the ''structure-loosening" behavior depicted in figure 2 is to be considered.…”

“…The results of studying the structure of liquid NM by the molecular-dynamic simulations [32,33] are also clearly indicative of C-HÁÁÁO hydrogen-bonding; herewith a sort of H-bonding in liquid NM is certainly more diffuse, less oriented, and less persistent than in water or alkanols [33]. However, some experimental studies based on comparing the volumetric [34] and Raman spectroscopic [35] properties of CH 3 NO 2 and CD 3 NO 2 have suggested that the hydrogen-bonding in liquid NM would be either very weak, or absent generally, a point being the subject of discussion hitherto [36].…”

A Molecular Dynamics Study of Classical Vibrational Spectra in Hydrostatically Compressed Crystalline Nitromethane

“…Ab initio and density-functional theory (DFT) calculations as well as simulations based on empirical force fields have been used to study the chemical and physical properties of nitromethane as functions of temperature and pressure. − These include calculations of crystal and liquid structures and transport coefficients, ,,,,,, melting, − crystallization, isothermal compression curves at zero Kelvin (“cold curves”) and other constitutive relationships, ,,,, electronic band gaps, ,, vibrational spectra, properties in the shocked state, ,,,,, and chemical reactivity. ,, Byrd et al showed convincingly, using plane-wave electronic-structure methods for several different energetic materials including nitromethane, that both standard and hybrid DFT significantly overestimate the unit cell volume as the complete basis set (CBS) limit is approached. More recently, Conroy et al reported plane-wave DFT calculations of hydrostatic and uniaxial compression of crystalline nitromethane.…”