Quantum-chemical analysis of small silver clusters

1987 ◽  
Vol 52 (7) ◽  
pp. 1652-1657 ◽  
Author(s):  
Grigorii V. Gadiyak ◽  
Yurii N. Morokov ◽  
Mojmír Tomášek
Keyword(s):  
Hard Spheres ◽  
Electronic Configuration ◽  
Close Packing ◽  
Basis Sets ◽  
Silver Clusters ◽  
Quantum Chemical Analysis ◽  
Spin Distribution ◽  
Spin Polarized ◽  
Atomic Silver ◽  
Equilibrium Geometries

Total energy calculations of three- and four-atomic silver clusters have been performed by the spin-polarized version of the CNDO/2 method to get the most stable equilibrium geometries, atomization energies, and charge and spin distribution on the atoms for three different basis sets: {s}, {sp}, and {spd}. When viewed from the equilateral triangle and square geometries, the last electronic configuration, i.e. the {spd} one, appears to be most stable with respect to the geometrical deformations considered. In this case, the behaviour of the atoms of both clusters resembles that of hard spheres (i.e. close-packing).

Few-Atomic Silver Clusters in Zeolites:  Ab Initio MO LCAO Calculation and Optical Spectroscopy

2000 ◽  
Vol 104 (51) ◽  
pp. 12105-12110 ◽  
Author(s):  
Valerij S. Gurin ◽  
Nina E. Bogdanchikova ◽  
Vitalii P. Petranovskii
Keyword(s):  
Ab Initio ◽  
Optical Spectroscopy ◽  
Silver Clusters ◽  
Lcao Calculation ◽  
Atomic Silver ◽  
Ab Initio Mo

The Fock-Space Coupled-Cluster Method in the Calculation of Excited State Properties

2005 ◽  
Vol 70 (6) ◽  
pp. 811-825 ◽  
Author(s):  
Monika Musiał ◽  
Leszek Meissner
Keyword(s):  
Experimental Data ◽  
Excited States ◽  
Fock Space ◽  
Hamiltonian Formulation ◽  
Basis Sets ◽  
Cluster Method ◽  
Coupled Cluster ◽  
Coupled Cluster Method ◽  
Excitation Energies ◽  
Equilibrium Geometries

Our recently developed intermediate Hamiltonian Fock-space coupled-cluster (FS-CC) method with singles and doubles is applied to calculation of equilibrium geometries, harmonic frequencies and adiabatic excitation energies for some excited states of N2 and CO. Due to the intermediate Hamiltonian formulation, which provides a robust computational scheme for solving the FS-CC equations, and the efficient factorization strategy, relatively large basis sets and reference spaces are employed permitting a comparison of calculated properties with experimental data.

New bounds on the sedimentation velocity for hard, charged and adhesive hard-sphere colloids

2011 ◽  
Vol 667 ◽  
pp. 403-425 ◽  
Author(s):  
W. TODD GILLELAND ◽  
SALVATORE TORQUATO ◽  
WILLIAM B. RUSSEL
Keyword(s):  
Brownian Motion ◽  
Upper Bound ◽  
Hard Sphere ◽  
Large Scale ◽  
Hard Spheres ◽  
Colloidal Dispersions ◽  
Sedimentation Velocity ◽  
Close Packing ◽  
Interparticle Potential ◽  
Equilibrium Microstructure

The sedimentation velocity of colloidal dispersions is known from experiment and theory at dilute concentrations to be quite sensitive to the interparticle potential with attractions/repulsions increasing/decreasing the rate significantly at intermediate volume fractions. Since the differences necessarily disappear at close packing, this implies a substantial maximum in the rate for attractions. This paper describes the derivation of a robust upper bound on the velocity that reflects these trends quantitatively and motivates wider application of a simple theory formulated for hard spheres. The treatment pertains to sedimentation velocities slow enough that Brownian motion sustains an equilibrium microstructure without large-scale inhomogeneities in density.

scholarly journals Optimized Geometry, Charge Distributions, Frontier Molecular Orbital Analysis and NLO Efficiency of BIS (4-Methoxyanilinium) Adipate by Quantum Chemical Calculations

2019 ◽  
Vol 9 (1S3) ◽  
pp. 329-340
Keyword(s):  
Charge Transfer ◽  
Quantum Chemical ◽  
Molecular Geometry ◽  
Basis Sets ◽  
Frontier Molecular Orbital ◽  
Mulliken Charge ◽  
Quantum Chemical Analysis ◽  
Molecular Orbital Analysis ◽  
Orbital Analysis ◽  
Good Agreement

In this work, optimized molecular geometry, vibrational and electronic properties of Bis(4-methoxylanilinium) adipate (4MAA) was obtained by Quantum chemical analysis using 6-311++G(d,p) basis sets. The experimental and computation vibrational spectra have been discussed. Experimental spectra of the 4MAA were recorded in the region 4000–400 cm-1 . The experimental and computational assignments were found to be in good agreement. FMO energies showed that charge transfer had occurred within the molecule. Mulliken charge distribution of the present compound was studied systematically. Furthermore, the hyperpolarizability calculations were analyzed.

scholarly journals ABSORPTION OF SOME SMALL SILVER CLUSTERS: DFT AND CASPT2 CALCULATIONS

2018 ◽  
Vol 55 (6A) ◽  
pp. 72
Author(s):  
Ngo Tuan Cuong
Keyword(s):  
Absorption Spectra ◽  
Density Functional ◽  
Noble Gas ◽  
Silver Cluster ◽  
Dft Method ◽  
Basis Sets ◽  
Silver Clusters ◽  
Excitation Energies ◽  
Complete Active Space ◽  
Td Dft

Two quantum chemical methods which are the time-dependent density functional theory (TD-DFT) and the complete active space CASPT2/CASSCF have been used in modeling absorption spectra of silver clusters Agn (n = 2, 3, 4, 6, 8). There is an overall good agreement between TD-DFT and CASPT2 results for transition energies. The absorption spectra of the Agn clusters examined can reasonably be simulated using the excitation energies obtained by either TD-DFT or CASPT2 method.  The main result emerged from this calculation is that the TD-DFT method is suitable for treatment of excited states of Ag clusters. The choice of specific functionals and basis sets to be used in some cases induces important effects on the calculated spectra. It is also noteworthy to mention that for some clusters, the neutral Ag6 for instance, the effect of noble gas environment is significant, while for some others such as the neutral Ag8, it is not. Therefore, carrying out TD-DFT calculations to reproduce and to assign a given structure to an experimental absorption spectrum of a silver cluster, it is not only to select suitable functionals but also to take enough effects of environments into account. 

The Force-Biased Algorithm for the Irregular Close Packing of Equal Hard Spheres

1989 ◽  
Vol 3 (4) ◽  
pp. 201-212 ◽  
Author(s):  
J. Mościński ◽  
M. Bargieł ◽  
Z. A. Rycerz ◽  
P. W. M. Jacobs
Keyword(s):  
Hard Spheres ◽  
Close Packing

scholarly journals Random-close packing limits for monodisperse and polydisperse hard spheres

Soft Matter ◽  
2014 ◽  
Vol 10 (21) ◽  
pp. 3826 ◽  
Author(s):  
Vasili Baranau ◽  
Ulrich Tallarek
Keyword(s):  
Hard Spheres ◽  
Close Packing ◽  
Random Close Packing
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