1,721,132 research outputs found
Linear chains of hydrogen molecules under pressure: An extreme-pressure continuum model study
No full textNew analytical gradients of the electronic energy of a confined molecular system within the extreme-pressure continuum model are presented and applied to the study of the equilibrium geometries of linear chains of hydrogen molecules nH 2 under pressures. The decrease in inter-and intramolecular H-H distances with the increase in the pressure has been studied up to 80 GPa. We have also shown that the compression of the bond-lengths can be interpreted in terms of the effect of the confining potential of the electron density of the molecular systems
The second derivative of the electronic energy with respect to the compression scaling factor in the XP-PCM model: Theory and applications to compression response functions of atoms
No full textWe present the analytical theory for the second derivative of the electronic energy with respect to the scaling factor of the compression cavity within the eXtreme pressure polarizable continuum model (XP-PCM) for the study of compressed atomic and molecular systems. The theory has been exploited to study compression response functions describing how the atomic/molecular properties are effected by an external pressure. The response functions considered include the atomic compressibility and the pressure coefficients of the ionization energy (IE) and electron affinity (EA). The theory has been validated by numerical application to compressed neon, argon, and krypton atoms
On the analytical evaluation of the pressure for the extreme-pressure polarizable continuum model (XP-PCM), with application to atoms
No full textWe review the analytical evaluation of the pressure within the extreme pressure polarizable continuum model for the study of compressed atoms and molecules. Furthermore, we present an effective interpretation of the confinement of the electron density in some noble gas atoms in terms of a simple first-order perturbation analysis of their occupied atomic orbitals
Excitonic splittng in conjugated molecular materials. A quantum mechanical model including interchain interactions and dielectric effects
No full textANALYTICAL EXPRESSIONS OF THE FREE-ENERGY DERIVATIVES FOR MOLECULES IN SOLUTION - APPLICATION TO THE GEOMETRY OPTIMIZATION
No full textA symmetry adapted tesselation of GEPOL surface: applications to molecular properties in solution
No full textAnalytical derivatives for molecular solutes .3. Hartree-Fock static polarizability and hyperpolarizabilities in the polarizable continuum model
No full textAb initio study of solvated molecules: A new implementation of the polarizable continuum model
No full textOn the calculation of local field factors for microscopic static hyperpolarizabilities of molecules in solution with the aid of quantum mechanical methods
No full textWe present a simple computational method to connect the computed ab initio values of static dipole polarizabilities and hyperpolarizabilities of molecules in solution with their experimental counterparts. The connection is done in terms of local field factors. We show that formulas used by experimentalists are not adequate, and that they can be replaced by a reformulation of the quantum-mechanical codes for the calculation of (hyper)polarizabilities in solution by using a realistic description of the solvent reaction field (i.e., a cavity withthepropermolecularshape). Thisreformulationleadstoanadditionalsetofhyperpolarizabilityvalues whichtakeintoaccountlocalmodificationstotheexternalstaticfield. Thissecondsetofvalueshasadirect relation with the macroscopic susceptibility tensors and, when compared to that derived from standard calculations, allows one to evaluate realistic local field factors
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