Study of structure and spectroscopy of water–hydroxide ion clusters: A combined simulated annealing and DFT-based approach

Abstract

In this paper, we explore the use of stochastic optimizer, namely simulated annealing (SA) followed by density function theory (DFT)-based strategy for evaluating the structure and infrared spectroscopy of (H 2 O) n OH − clusters where n = 1-6. We have shown that the use of SA can generate both global and local structures of these cluster systems. We also perform a DFT calculation, using the optimized coordinate obtained from SA as input and extract the IR spectra of these systems. Finally, we compare our results with available theoretical and experimental data. There is a close correspondence between the computed frequencies from our theoretical study and available experimental data. To further aid in understanding the details of the hydrogen bonds formed, we performed atoms in molecules calculation on all the global minimum structures to evaluate relevant electron densities and critical points.

Activation of CO2 in Photoirradiated CO2–H2O Clusters: Direct Ab Initio Molecular Dynamics (MD) Study

“…Direct ab initio MD calculations on the excited CT state PES were carried out as follows. First, the density matrix of the cluster ion on the CT state at time zero was calculated by the complete active space self-consistent field (CASSCF) method with five electrons distributed in six orbitals, namely, CASSCF (5,6). The initial guess of the cluster cation was thus obtained.…”

The Nanostructure of HMT-PMBI, a Sterically Hindered Ionene

“…We used the TIP4P/2005 water model to describe the water molecules, 31 halide parameters previously determined by fits to experimental hydration energies, 32 and hydroxide ion parameters based on TIP3P water with a proton removed and the remaining negative charge assigned to the oxygen. 33 We used E improper = K I (1 + d cos(nϕ)) to describe some improper dihedral angles when recommended by the LigParGen server. 30 However, the unusual rotational barriers and cationic groups required special attention.…”

Reactivity of Hydrated Hydroxide Anion Clusters with H and Rb: An ab Initio Study

“…The VDE of the anion, the dipole moment of the neutral core, the partial charge on the O atom of the hydroxide group and the rotational constant of the OH(H 2 O) − n clusters are reported in Table I along with the value obtained by Masamura 37 and S. Guha et al 51 using the MP2/AVDZ and DFT methods, respectively, and the CCSD(T) results from Morita et al 52 . The dipole moment varies greatly between the structures.…”