A novel VU-MRCC formalism for the simultaneous treatment of strong relaxation and correlation effects with applications to electron affinity of neutral radicals

2006 ◽  
Vol 329 (1-3) ◽  
pp. 290-306 ◽  
Author(s):  
Debasis Jana ◽  
Dipayan Datta ◽  
Debashis Mukherjee
Keyword(s):  
Electron Affinity ◽  
Correlation Effects ◽  
Simultaneous Treatment ◽  
Strong Relaxation

Strong Relaxation and Correlation Effects on the 2p53s–2p6Spectrum of Neutral Neon

2003 ◽  
Vol 146/147 (1-4) ◽  
pp. 161-170 ◽  
Author(s):  
C. Z. Dong ◽  
L. Y. Xie ◽  
X. X. Zhou ◽  
X. W. Ma ◽  
S. Fritzsche
Keyword(s):  
Correlation Effects ◽  
Strong Relaxation

Relativistic and Electron Correlation Effects as a Tool for Explaining Some Trends in Molecular Properties and Interactions

2006 ◽  
Vol 1 (1) ◽  
pp. 259-265 ◽  
Author(s):  
Miroslav Urban ◽  
Vladimír Kellö
Keyword(s):  
Electron Affinity ◽  
Electron Correlation ◽  
Heavy Atom ◽  
Lone Pair ◽  
Relativistic Effects ◽  
Electric Properties ◽  
Molecular Properties ◽  
Cluster Method ◽  
Correlation Effects ◽  
Electron Correlation Effects

In this paper we discuss relatively routine Douglas–Kroll–Hess spin–free relativistic calculations as a tool for understanding some trends of molecular properties within the series of related molecules. Electron correlation effects are considered by the Coupled Cluster method with iterative treatment of the single and double excitation operators and perturbative treatment of triples, CCSD(T). For our analysis we use accumulated data on relativistic effects on ionization potentials, electron affinities and polarizabilities of the coinage elements, Cu, Ag, and Au and related series like Ia and IIa group elements. Next we analyze electric properties of diatomic molecules as CuF, AgF, and AuF, and compare electric properties and bonding energies of these molecules with intermetalics CuAl, AgAl, AuAl. Electric dipole moments and dipole polarizabilities of the series of oxides including a heavy atom, GeO, SnO, and PbO in their 1∑ ground states are also analyzed. Particular attention is paid to the dissociation energy of PbO and its electron affinity. The bonding character of the MeL series of complexes (Me=Cu, Ag, Au; L=H2O, NH3, and H2S) is explained by stressing the importance of the charge transfer from the lone pair of the ligand to the metal element. Relativistic effects which affect the Me electron affinity and polarizability facilitate understanding the trends of Me interactions with different ligands. We also mention using of the optimized virtual orbital space (OVOS) as an instrument which allows to circumvent problems with proper contraction needed for a specific approximate relativistic Hamiltonian. OVOS allows to reduce the computer time of correlated relativistic calculation by an order of magnitude.

What correlation effects are covered by density functional theory?

2000 ◽  
Vol 98 (20) ◽  
pp. 1639-1658 ◽  
Author(s):  
Yuan He, Jurgen Grafenstein, Elfi Kraka,
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Correlation Effects ◽  
Functional Theory

Correlation effects in double ionization of magnesium atom

1999 ◽  
Vol 09 (PR6) ◽  
pp. Pr6-101-Pr6-103 ◽  
Author(s):  
S. El Ghazouani ◽  
P. A. Hervieux ◽  
C. Dal Cappello ◽  
J. Langlois
Keyword(s):  
Double Ionization ◽  
Correlation Effects ◽  
Magnesium Atom

Polysulfide-borohydride modification of southern pine alkaline pulping integrated with hydrothermal pre-extraction of hemicelluloses

TAPPI Journal ◽  
2011 ◽  
Vol 10 (7) ◽  
pp. 9-16
Author(s):  
SUNG-HOON YOON ◽  
HARRY CULLINAN ◽  
GOPAL A. KRISHNAGOPALAN
Keyword(s):  
Loblolly Pine ◽  
Sodium Borohydride ◽  
Kraft Pulping ◽  
Hot Water ◽  
Pulp Yield ◽  
Paper Strength ◽  
Southern Pine ◽  
Two Stage ◽  
Simultaneous Treatment ◽  
Process Modification

We studied three process modifications to investigate their effects on the property and yield recovery capabilities of kraft pulping integrated with hemicellulose pre-extraction of southern pine. Loblolly pine chips were pre-extracted with hot water until the sugar extraction yield reached the targeted value of 10% and then subjected to conventional and modified kraft pulping. Modification included polysulfide pretreatment; polysulfide-sodium borohydride dual pretreatment, and polysulfide followed by polysulfide-sodium borohydride dual pretreatment two-stage pretreatments prior to kraft pulping. In the first modification, about 5% of the lost pulp yield (total 7%) caused by hemicellulose pre-extraction could be recovered with 15%-20% polysulfide pretreatment. Complete recovery (7%) was achieved with simultaneous pretreatment using 15% polysulfide and 0.5% sodium borohydride with 0.1% anthraquinone in polysulfide-sodium borohydride dual pretreatment. Two-stage pretreatment using recycled 15% polysulfide followed by simultaneous treatment of 6% polysulfide and 0.4%–0.5% sodium borohydride with 0.1% anthraquinone also achieved 100% yield recovery. Continuous recycling of 15% polysulfide employed in the two-stage process modification maintained its yield protection efficiency in a repeated recycling cycle. No significant changes in paper strength were found in handsheets prepared from the three process modifications, except for a minor reduction in tear strength.

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