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  • 1
    Electronic Resource
    Electronic Resource
    Ab initio configuration interaction study of the electronic and geometric structure of small, mixed neutral and cationic MgNak and MgLik (k=2–8) clusters (1989)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 91 (1989), S. 4229-4241 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Neutral and cationic MgYk clusters with Y=Na, Li (k=2–8) have been investigated using all-electron ab initio configuration interaction (CI) procedures. The alkaline earth metal (or group IIa) atom takes the central position in the most stable geometries of all clusters studied except for MgNa3, MgLi3, and MgNa+3 . The importance of the chemical nature of the atoms involved in determining the stability and other properties of the clusters, is clearly demonstrated by comparing the neutral and cationic series of MgNak , MgLik , and BeLik . The properties obtained can be fully explained by considering the s–p promotion, the role of Jahn–Teller distortions, and the stereochemical aspects. The appropriate treatment of electronic correlation effects is of crucial importance for correctly predicting the stability of the clusters. The low stability of small clusters, especially MgNak (k〈5), is particularly noticeable. The atomization energies per atom for MgY6, MgY7, and MgY8 with Y=Na or Li, are all found to be comparable. The general pattern for atomization energies per atom and for other stability measures as well as for fragmentation channels and ionization potentials as functions of the cluster size is explained in the paper.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.456802
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  • 2
    Electronic Resource
    Electronic Resource
    Ab initio configuration-interaction study of the photoelectron spectra of small sodium cluster anions (1989)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 91 (1989), S. 3794-3795 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: We find that the ab initio direct configuration-interaction calculations on Na−2–5 and Na2–5 account for the observed patterns of photoelectron spectra, reproduce the observed excitation energies in a semiquantitative way and permit an assignment of cluster geometries.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.456862
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  • 3
    Electronic Resource
    Electronic Resource
    Ab initio predictions of structural and optical response properties of Na+n clusters: Interpretation of depletion spectra at low temperature (1996)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 104 (1996), S. 1427-1440 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: We show that a comparison of the depletion spectra of Na+n (n=2–9,11,21) clusters recorded at low temperature and optically allowed transitions determined for the stable structures using ab initio methods accounting for electron correlation allows the assignment of the cluster geometry to the measured features. Due to the large mobility of atoms in alkali metal clusters, the influence of temperature on structural and electronic properties is significant. The lowering of temperature reveals new spectroscopic features which are structure dependent. Optical response properties of small cationic Na+n clusters are characterized by rich molecularlike spectroscopic patterns, also with increasing size, and differ substantially from those found for neutral clusters. It has been clearly demonstrated that not only the number of valence electrons but its mutual interplay with the geometric properties determine optical response features. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.470909
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  • 4
    Electronic Resource
    Electronic Resource
    Electronic properties and geometric structures of Li4H and Li9H from optical absorption spectra (1995)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 102 (1995), S. 2727-2736 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Optical absorption spectra of Li4H and Li9H clusters have been recorded by depletion spectroscopy in the visible range. From comparison with ab initio calculations, geometries of both clusters are identified. The hydrogen atom assumes a peripheral position bridging two and three Li atoms in the planar and three-dimensional structures of Li4H and Li9H, respectively. Na4F and Na9F clusters are also theoretically studied and it is shown how the strong electronegativity of the F atom leads to different geometries than in lithium hydrids. Finally, the metallic character of these clusters is discussed and in both cases, the hydrogen or fluorine atom localizes one valence electron. However, the optical absorption spectra are much broader than in pure Lin and Nan clusters due to the lower symmetry. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.468649
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  • 5
    Electronic Resource
    Electronic Resource
    Molecular bonding with scandium: Diatomics ScH, ScO, ScC, and ScN (1988)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 88 (1988), S. 3747-3760 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The spectroscopic and chemical properties of some typical diatomics of scandium are calculated using a nonempirical HF pseudopotential and multireference single-and-double configuration interaction. The potential energy curves of ScO, where the ground state (2∑+) is clearly separated from other low-lying states (2Δ,2Π, and 4Π), are in good agreement with experimental data, and the strong bonding is paralleled with a significant ionic nature. All six lowest states (1∑+,3∑+,1Π,3Π,1Δ, and 3Δ) of ScH dissociating into the ground state atoms have a common bonding orbital and they can only be distinguished from each other by the orbital(s) used by the two nonbonding Sc electrons and their relative spin dispositions. The ScC molecule has about the same stability as ScH with respect to dissociation of the ground state, but the former shows a more complicated bonding nature in its lowest states (2∑+,2Π,2Δ,4∑−,4∑+,4Π, and 4Δ). Highly degenerate bound states 5Δ,5Π, and 3∑− of ScN appear to be the least bonding among the heteronuclear diatomics studied here. The estimated binding energies obtained from these calculations are about 2.0 eV for ScH and ScC, and 1.0 eV for ScN. The different characteristics of the lowest Sc atomic states which are due to different 3d and 4s occupations are analyzed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.453874
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  • 6
    Electronic Resource
    Electronic Resource
    Surgical tactics in the treatment of malignant renal tumors in childhood (1997)
    Springer
    Pediatric surgery international 12 (1997), S. 145-147 
    Details
    ISSN: 1437-9813
    Keywords: Key words Malignant renal tumors ; Wilms’ tumor ; Ureteronephrectomy ; Favorable histology ; Unfavorable histology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The authors report the treatment results of 89 children with renal tumors (excluding carcinoma) seen from 1988 to 1992, 71 (79.8%) with favorable-histology Wilms’ tumor (survival 86%) and 18 (20.2%) with unfavorable histology, including anaplastic nephroblastoma, clear-cell sarcoma, and rhabdoid tumor (survival 61%). Preoperative chemotherapy (ChT) was given to 46 patients (survival 84%); none was given to 43 with either tumors in the 1st year of life, massive hematuria, or tumor growth during ChT (survival 78%). There were 3 tumor ruptures in the latter group compared to 1 in the former group.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003830050088
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  • 7
    Electronic Resource
    Electronic Resource
    Surgical tactics in the treatment of malignant renal tumors in childhood (1997)
    Springer
    Pediatric surgery international 12 (1997), S. 145-147 
    Details
    ISSN: 1437-9813
    Keywords: Malignant renal tumors ; Wilms' tumor ; Ureteronephrectomy ; Favorable histology ; Unfavorable histology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The authors report the treatment results of 89 children with renal tumors (excluding carcinoma) seen from 1988 to 1992, 71 (79.8%) with favorable-histology Wilms' tumor (survival 86%) and 18 (20.2%) with unfavorable histology, including anaplastic nephroblastoma, clear-cell sarcoma, and rhabdoid tumor (survival 61%). Preoperative chemotherapy (ChT) was given to 46 patients (survival 84%); none was given to 43 with either tumors in the 1st year of life, massive hematuria, or tumor growth during ChT (survival 78%). There were 3 tumor ruptures in the latter group compared to 1 in the former group.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01349984
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  • 8
    Electronic Resource
    Electronic Resource
    Quantum chemical study of electronic and dynamic properties of metal and mixed non-stoichiometric clusters (1998)
    Springer
    Czechoslovak journal of physics 48 (1998), S. 637-658 
    Details
    ISSN: 1572-9486
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The aim of this contribution is to show that quantum chemistry has suitable tools to extract the specific properties of small metallic and mixed non-stoichiometric clusters which cannot be obtained by extrapolation from the bulk properties to the atom. For this purpose, first the main features of the methods used for the calculations of the ground and excited states of clusters valid at zero temperature (T = 0) will be sketched and the factors determining accuracy of results will be pointed out. The structural and optical response properties of cationic clusters as a function of size will be presented and compared with experimental data. The series of non-stoichiometric alkali-halide clusters containing single and multiple excess electrons will serve as prototypes to study a possible “metal-insulator transition” and “segregation into metallic and ionic parts” in finite systems. Second, an outline of ab initio molecular dynamics methods based on gradient corrected density functional approach with gaussian basis used for determination of temperature dependent ground state properties will be presented. Different temperature behavior of distinct type of structures will be illustrated on an example of cluster.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1021489605971
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  • 9
    Electronic Resource
    Electronic Resource
    General principles governing structures of small clusters (1986)
    Springer
    The European physical journal 3 (1986), S. 147-153 
    Details
    ISSN: 1434-6079
    Keywords: 7300
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract General rules which govern electronic and geometric structures of small clusters are formulated, and their validity is documented with the results of the MRD - CI investigations for Li n , BeLi k , Be l (n=2−14,k=2−6,l=2−13) as well as on IIa and IVa tetramers. The MRD - CI results are compared with investigations performed with other methods.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01384800
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  • 10
    Electronic Resource
    Electronic Resource
    Core-valence correlation potentials based on density functional theory. Applications to valence-electron-only calculations on Na and K diatomics (1989)
    Springer
    The European physical journal 13 (1989), S. 355-361 
    Details
    ISSN: 1434-6079
    Keywords: 31.20 ; 36.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The core-valence correlation potential has been derived for Na and K employing atomic calculations which make use of the density functional formula worked out by Lee, Yang and Parr based on Colle-Salvetti approach. The numerical potential is fitted with a small number of Gaussians leading to a very simple expression for an one-electron corevalence correlation operatorŴ cv . The core-valence correlation corrections can be computed by applyingŴ cv on a quite general class of wavefunctions. Applications of theŴ cv operator within the framework of valence-electron-only calculations using effective Hamiltonians are presented for Na and K atoms, for Na2, K2, NaK and their cations. Almost all the corrections calculated for the physical properties due to the core-valence correlation lead to results which are in good agreement with those obtained from much more sophisticated treatments and experimental data.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01398902
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