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George Maroulis

Bio: George Maroulis is an academic researcher from University of Patras. The author has contributed to research in topics: Polarizability & Dipole. The author has an hindex of 43, co-authored 222 publications receiving 5767 citations. Previous affiliations of George Maroulis include University of New Brunswick & Université catholique de Louvain.


Papers
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Journal ArticleDOI
TL;DR: The electric multipole moments, dipole and quadrupole polarizability and hyperpolarizability of hydrogen chloride have been determined from an extensive and systematic study based on finite-field fourth-order many-body perturbation theory and coupled-cluster calculations as discussed by the authors.
Abstract: The electric multipole moments, dipole and quadrupole polarizability and hyperpolarizability of hydrogen chloride have been determined from an extensive and systematic study based on finite-field fourth-order many-body perturbation theory and coupled-cluster calculations. Our best values for the dipole, quadrupole, octopole and hexadecapole moment at the experimental internuclear separation of Re=2.408 645a0 are μ=0.4238ea0, Θ=2.67ea02, Ω=3.94ea03, and Φ=13.37ea04, respectively. For the mean and the anisotropy of the dipole polarizability ααβ we recommend ᾱ=17.41±0.02 and Δα=1.60±0.03e2a02Eh−1. For the mean value of the first dipole hyperpolarizability βαβγ we advance β=−6.8±0.3e3a03Eh−2. Extensive calculations with a [8s6p6d3f/5s4p2d1f] basis set at the CCSD(T) level of theory yield the R-dependence of the Cartesian components and the mean of the second dipole hyperpolarizability γαβγδ(R)/e4a04Eh−3 around Re as γzzzz(R)=1907+1326(R−Re)+570(R−Re)2+10(R−Re)3−40(R−Re)4, γxxxx(R)=3900+747(R−Re)−65(R−Re)2−38...

191 citations

Journal ArticleDOI
TL;DR: In this article, the Hartree-Fock limit for the mean hyperpolarizability is estimated at γ=715±4e4a04Eh−3 at the experimental bond length Re=2.074 32a0.
Abstract: We report accurate values of the electric moments, static polarizabilities, hyperpolarizabilities and their respective derivatives for N2. Our values have been extracted from finite-field Moller–Pleset perturbation theory and coupled cluster calculations performed with carefully designed basis sets. A large [15s12p9d7f] basis set consisting of 290 CGTF is expected to provide reference self-consistent-field values of near-Hartree–Fock quality for all properties. The Hartree–Fock limit for the mean hyperpolarizability is estimated at γ=715±4e4a04Eh−3 at the experimental bond length Re=2.074 32a0. Accurate estimates of the electron correlation effects were obtained with a [10s7p6d4f] basis set. Our best values are Θ=−1.1258ea02 for the quadrupole and Φ=−6.75ea04 for the hexadecapole moment, ᾱ=11.7709 and Δα=4.6074e2a02Eh−1 for the mean and the anisotropy of the dipole polarizability, C=41.63e2a04Eh−1 for the mean quadrupole polarizability and γ=927e4a04Eh−3 for the dipole hyperpolarizability. The latter v...

133 citations

Journal ArticleDOI
TL;DR: In this paper, a complete description of the electric dipole moment (μ), the dipole polarizability (α), the first dipole (β), and the second dipole hyperpolarizability tensors is reported for the ground state of the water molecule at its equilibrium geometry.
Abstract: A complete description of the electric dipole moment (μ), the dipole polarizability (α), the first dipole (β), and the second dipole (γ) hyperpolarizability tensors is reported for the ground state of the water molecule at its equilibrium geometry. Self‐consistent‐field (SCF) and complete fourth‐order many‐body perturbation theory (MP4) values of the independent components are calculated via a finite‐field method from the perturbed energies of the molecule in the presence of a homogeneous electric field. The dependence of the calculated values on the basis set is studied at both the SCF and the MP4 levels. Electron correlation has a strong effect on the hyperpolarizability. Our best SCF values are calculated with a large (13s10p6d2f/9s6p2d)[9s7p6d2f/6s5p2d] basis set comprising 136 contracted Gaussian‐type functions and are 0.7789 ea0 for the dipole moment and 8.531 e2a20E−1h, −10.86 e3a30E−2h, and 979 e4a40E−3h for the mean dipole polarizability and first and second dipole hyperpolarizabilities, respectively. The electron correlation correction to these properties is estimated at −0.055±0.005 ea0, 1.11±0.14 e2a20E−1h, −7.1±1.3 e3a30E−2h, and 749±113 e4a40E−3h. Agreement with experiment is very good for the dipole moment and mean dipole polarizability. As regards the hyperpolarizability, satisfactory agreement with the frequency‐dependent values of Ward and Miller may also be deduced, but further experimental and theoretical work on the dispersion of the hyperpolarizability is needed for an effective rapprochement of theory and experiment.

130 citations

Journal ArticleDOI
TL;DR: In this article, an extensive investigation of the electric dipole moment (μα), static polarizability (ααβ), and hyperpolarizability of the water dimer was performed at both rigid and relaxed monomer geometries.
Abstract: We report an extensive investigation of the electric dipole moment (μα), static polarizability (ααβ), and hyperpolarizability (βαβγ and γαβγδ) of the water dimer. Calculations were performed at both rigid and relaxed monomer geometries. At the rigid monomer geometry (RIMG), a very large [9s6p6d4f/6s5p3d2 f] basis set consisting of 370 Gaussian-type functions is thought to provide self-consistent field (SCF) values very close to the Hartree–Fock limit for all properties: total dipole moment μ=1.0706ea0, mean and anisotropy of the dipole polarizability ᾱ=16.98 and Δα=2.69e2a02Eh−1, first hyperpolarizability (in the direction of the dipole moment vector) β=−2.9e3a03Eh−2, and mean second dipole hyperpolarizability γ=1906e4a04Eh−3. Very large electron correlation effects are observed for the hyperpolarizability. At the CCSD(T) level, coupled-cluster theory with single, double and perturbatively linked triple excitations, our best values are μ=1.0204ea0, ᾱ=19.54, and Δα=3.06e2a02Eh−1, β=−6.5e3a03Eh−2, and γ=3669e4a04Eh−3. ᾱ((H2O)2) and γ((H2O)2) are not drastically different than twice the size of ᾱ(H2O) and γ(H2O). Our efforts to estimate the interaction properties of two water molecules in the dimer lead to the conclusion that ᾱinter and γinter are rather small. Further calculations at a relaxed monomer geometry (REMG) corroborate this conclusion. We have fully explored basis set effects at all levels of theory and for all properties. We rely on a sequence of small-sized but sufficiently flexible basis sets in order to propose reliable computational strategies for the extension of electric property calculations to large water clusters.

129 citations

Journal ArticleDOI
TL;DR: Molecular orbital and adaptive natural density partitioning analyses indicate that the enhanced stability of half-sandwich TaB12- is due to the strong interaction of the Ta atom with surrounding B atoms and σ B-B bonds in the B12 moiety.
Abstract: Transition-metal (TM)-doped boron clusters have received considerable attention in recent years, in part, because of their remarkable size-dependent structural and electronic properties. However, the structures of medium-sized boron clusters doped with TM atoms are still not well-known because of the much increased complexity of the potential surface as well as the rapid increase in the number of low-energy isomers, which are the challenges in cluster structural searches. Here, by means of an unbiased structure search, we systematically investigated the structural evolution of medium-sized tantalum-doped boron clusters, TaBn0/- (n = 10-20). The results revealed that TaBn0/- (n = 10-15) clusters adopt half-sandwich molecular geometries, with the notable exception of TaB10-, while for n = 16-18 and 19-20, the lowest-energy clusters are characterized by drum-type geometries and tubular molecules with two B atoms on the top, respectively. Good agreement between the calculated and experimental photoelectron spectra strongly support the validity of our global minimum structures. Molecular orbital and adaptive natural density partitioning analyses indicate that the enhanced stability of half-sandwich TaB12- is due to the strong interaction of the Ta atom (5d orbitals) with surrounding B atoms (2p orbitals) and σ B-B bonds in the B12 moiety.

125 citations


Cited by
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TL;DR: In this paper, a systematic study of the basis sets required to obtain accurate correlated values for the static dipole (α1), quadrupole(α2), and octopole (β) polarizabilities and the hyperpolarizability (γ) of the rare gas atoms He, Ne, and Ar were presented.
Abstract: An accurate description of the electrical properties of atoms and molecules is critical for quantitative predictions of the nonlinear properties of molecules and of long‐range atomic and molecular interactions between both neutral and charged species. We report a systematic study of the basis sets required to obtain accurate correlated values for the static dipole (α1), quadrupole (α2), and octopole (α3) polarizabilities and the hyperpolarizability (γ) of the rare gas atoms He, Ne, and Ar. Several methods of correlation treatment were examined, including various orders of Moller–Plesset perturbation theory (MP2, MP3, MP4), coupled‐cluster theory with and without perturbative treatment of triple excitations [CCSD, CCSD(T)], and singles and doubles configuration interaction (CISD). All of the basis sets considered here were constructed by adding even‐tempered sets of diffuse functions to the correlation consistent basis sets of Dunning and co‐workers. With multiply‐augmented sets we find that the electrical properties of the rare gas atoms converge smoothly to values that are in excellent agreement with the available experimental data and/or previously computed results. As a further test of the basis sets presented here, the dipole polarizabilities of the F− and Cl− anions and of the HCl and N2 molecules are also reported.

2,376 citations

01 Feb 1995
TL;DR: In this paper, the unpolarized absorption and circular dichroism spectra of the fundamental vibrational transitions of the chiral molecule, 4-methyl-2-oxetanone, are calculated ab initio using DFT, MP2, and SCF methodologies and a 5S4P2D/3S2P (TZ2P) basis set.
Abstract: : The unpolarized absorption and circular dichroism spectra of the fundamental vibrational transitions of the chiral molecule, 4-methyl-2-oxetanone, are calculated ab initio. Harmonic force fields are obtained using Density Functional Theory (DFT), MP2, and SCF methodologies and a 5S4P2D/3S2P (TZ2P) basis set. DFT calculations use the Local Spin Density Approximation (LSDA), BLYP, and Becke3LYP (B3LYP) density functionals. Mid-IR spectra predicted using LSDA, BLYP, and B3LYP force fields are of significantly different quality, the B3LYP force field yielding spectra in clearly superior, and overall excellent, agreement with experiment. The MP2 force field yields spectra in slightly worse agreement with experiment than the B3LYP force field. The SCF force field yields spectra in poor agreement with experiment.The basis set dependence of B3LYP force fields is also explored: the 6-31G* and TZ2P basis sets give very similar results while the 3-21G basis set yields spectra in substantially worse agreements with experiment. jg

1,652 citations

Journal ArticleDOI
TL;DR: The development of wave optics for light brought many new insights into our understanding of physics, driven by fundamental experiments like the ones by Young, Fizeau, Michelson-Morley and others as mentioned in this paper.
Abstract: The development of wave optics for light brought many new insights into our understanding of physics, driven by fundamental experiments like the ones by Young, Fizeau, Michelson-Morley and others. Quantum mechanics, and especially the de Broglie’s postulate relating the momentum p of a particle to the wave vector k of an matter wave: k = 2 λ = p/ℏ, suggested that wave optical experiments should be also possible with massive particles (see table 1), and over the last 40 years electron and neutron interferometers have demonstrated many fundamental aspects of quantum mechanics [1].

1,194 citations

Book
09 Jan 2011
TL;DR: In this paper, a comprehensive and richly illustrated textbook on the astrophysics of the interstellar and intergalactic medium is presented, including the gas and dust, as well as the electromagnetic radiation, cosmic rays, and magnetic and gravitational fields, present between the stars in a galaxy and also between galaxies themselves.
Abstract: This is a comprehensive and richly illustrated textbook on the astrophysics of the interstellar and intergalactic medium--the gas and dust, as well as the electromagnetic radiation, cosmic rays, and magnetic and gravitational fields, present between the stars in a galaxy and also between galaxies themselves. Topics include radiative processes across the electromagnetic spectrum; radiative transfer; ionization; heating and cooling; astrochemistry; interstellar dust; fluid dynamics, including ionization fronts and shock waves; cosmic rays; distribution and evolution of the interstellar medium; and star formation. While it is assumed that the reader has a background in undergraduate-level physics, including some prior exposure to atomic and molecular physics, statistical mechanics, and electromagnetism, the first six chapters of the book include a review of the basic physics that is used in later chapters. This graduate-level textbook includes references for further reading, and serves as an invaluable resource for working astrophysicists. * Essential textbook on the physics of the interstellar and intergalactic medium * Based on a course taught by the author for more than twenty years at Princeton University * Covers radiative processes, fluid dynamics, cosmic rays, astrochemistry, interstellar dust, and more * Discusses the physical state and distribution of the ionized, atomic, and molecular phases of the interstellar medium * Reviews diagnostics using emission and absorption lines * Features color illustrations and detailed reference materials in appendices * Instructor's manual with problems and solutions (available only to teachers)

1,143 citations

Journal ArticleDOI
01 Sep 2017-IUCrJ
TL;DR: The accurate and efficient CE-B3LYP and CE-HF model energies for intermolecular interactions in molecular crystals are extended to a broad range of crystals by calibration against density functional results for molecule/ion pairs extracted from 171 crystal structures.

704 citations