ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Bonding and stabilities of small silicon clusters: A theoretical study of Si7–Si10 (1988)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 89 (1988), S. 2219-2234 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Ab initio calculations have been performed to study the structures and energies of intermediate-sized silicon clusters (Sin, n=7–10). All geometries have been optimized at the Hartree–Fock (HF) level of theory with the polarized 6-31G* basis set. The harmonic vibrational frequencies have been evaluated at the HF/6-31G* level of theory. Electron correlation effects have been included by means of fourth order Møller–Plesset perturbation theory. The most stable structure for Si7 is a pentagonal bipyramid and the lowest energy calculated structures for Si8–Si10 correspond to capped octahedral or prismatic geometrical arrangements. The evolution of the cluster geometries with increasing size is discussed. Clusters containing four, six, seven, and ten atoms have been identified as "magic numbers'' for small silicon clusters, both theoretically and experimentally. The hybridization and bonding in small silicon clusters is discussed. Our results are used to interpret the recent photoelectron spectra of negative silicon cluster ions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.455065
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Theoretical characterization of the potential energy surface for H+O2→HO*2→HO+O. II. The potential for H atom exchange in HO2 (1989)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 91 (1989), S. 2373-2375 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The results of CASSCF/multireference contracted CI calculations with large ANO basis sets are presented for the exchange region of the HO2 potential energy surface. The saddle point for H atom exchange is ≈13 kcal/mol below the energy of H+O2; therefore, this region of the surface will be accessible during H+O2 recombination and metathesis reactions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.457047
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Theoretical characterization of the minimum energy path for hydrogen atom addition to N2: Implications for the unimolecular lifetime of HN2 (1989)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 90 (1989), S. 3230-3240 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The minimum energy path (MEP) for the addition of a hydrogen atom to N2 is characterized in CASSCF/externally contracted CI calculations using a [4s3p2d1f/3s2p1d] ANO basis set, with additional single point calculations at the stationary points of the potential energy surface using a [5s4p3d2f/4s3p2s] ANO basis set. These calculations represent the most extensive set of ab initio calculations on HN2 completed to date, yielding a zero-point corrected barrier for HN2 dissociation of ≈8.5 kcal mol−1. The lifetime of the HN2 species is estimated from the calculated geometries and energetics using both conventional transition state theory and a method which utilizes an Eckart barrier to compute one-dimensional quantum mechanical tunneling effects. This study concludes that the lifetime of the HN2 species is very short, greatly limiting its role in combustion processes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.455875
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    The structure and bonding of F2O2 (1987)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 86 (1987), S. 4518-4522 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The geometry of F2O2 is determined by several ab initio methods, including Møller–Plesset perturbation theory (MP) based on an RHF reference and externally contracted configuration interaction (CCI) based on a complete-active-space (CAS) reference. Basis sets with polarization and diffuse functions are used. Compared to the gas-phase experimental structure, SCF and MP bond lengths are very poor, and the MP geometries vary considerably with basis set changes. Three sizes of CAS are examined and each results in a dissociative surface. Only CCI calculations from a large CAS produce a geometry in reasonable agreement with experiment. After addition of Davidson's correction, the remaining errors in the O–O and O–F bond lengths are 0.016 and 0.025 A(ring), respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.452727
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Electronic structures of the negative ions Si−2 –Si−10: Electron affinities of small silicon clusters (1991)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 94 (1991), S. 3670-3678 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Accurate ab initio calculations have been performed to investigate the structures and energies of the negative ions of Si2–Si10. The effects of polarization functions, diffuse functions, and electron correlation have been included in these calculations. In most cases, there is a good correspondence between the ground state structures of the negative ions and those of the corresponding neutral species. Adiabatic electron affinities are computed and compared with recent experimental measurements. Si3, Si5, Si8, and Si9 are found to have electron affinities which are larger than their neighbors. This result is interpreted using our previous calculations on the low-lying states of the corresponding neutral species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.459738
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Structures and stabilities of sulfur clusters (1990)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 93 (1990), S. 5862-5874 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The geometric structures and relative stabilities of small sulfur clusters (S2–S12) are explored by means of ab initio quantum chemical calculations. The effects of polarization functions and electron correlation are included in these calculations. Open forms are more stable for the small clusters up to S4 whereas ring structures are favored for the larger clusters. The stereochemical aspects of cyclo-S5 and cycle-S6 exhibit features very similar to that of the valence-isoelectronic hydrocarbons cyclopentane and cyclohexane. The calculated geometries of S6–S8 and S10–S12 are all in excellent agreement with the experimentally determined structures. Vibrational frequencies have been computed and are compared with experimental data. The relative stabilities of the different sulfur rings are compared to each other.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.459583
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Theoretical characterization of the lowest three potential surfaces of HNO. I. The potential for H atom addition to NO (1989)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 91 (1989), S. 2939-2948 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The results of complete active space SCF/multireference contracted CI(CASSCF/CCI) calculations with large atomic natural orbital (ANO) basis sets are presented for the H + NO region of the lowest three potential surfaces of HNO (1A', 3A‘, and 1A‘). The calculations focus on the minimum energy path for H atom addition to the N end of NO and on the equilibrium geometry region of HNO and HON.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.456964
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Erratum: Theoretical characterization of the minimum energy path for the reaction H+O2→HO2*→HO+O [J. Chem. Phys. 88, 6273 (1988)] (1989)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 90 (1989), S. 7613-7613 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.456711
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Theoretical characterization of the minimum energy path for the reaction H+O2→HO2*→HO+O (1988)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 88 (1988), S. 6273-6281 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The potential energy surface for the reaction H+O2→HO@B|2 →HO+O has been characterized in the vicinity of the minimum energy path using CASSCF/contracted CI calculations with a basis set which is triple zeta valence quality plus three sets of polarization functions. CASSCF/CI calculations were carried out along the CCI minimum energy path. The latter calculation shows essentially no barrier for addition of an H atom to O2, in agreement with predictions made in earlier studies. The potential surface for recombination of OH and O is complicated by a crossing, at rOO (approximate)5.5a0, between the surface for electrostatic (OH dipole–O quadrupole) interaction and that for the formation of an O–O chemical bond. This surface crossing results in a small ((approximate)0.5 kcal/mol) barrier.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.454466
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    SiC2: A molecular pinwheel (1994)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 100 (1994), S. 4110-4126 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: We present the results of a combined experimental and theoretical study of the large-amplitude motion in SiC2 in which the C2 fragment undergoes hindered internal rotation. Stimulated emission pumping (SEP) is used to obtain rovibrational term energies for levels with up to 14 quanta of excitation in the large-amplitude vibration. We analyze the SEP data, as well as other available experimental data, using a semirigid bender model that allows for complete internal rotation within a triatomic molecule. From the least-squares fitting of this model to the data, we determine the potential energy along the minimum energy path of the large-amplitude vibration, the harmonic energies of the small-amplitude vibrations, and the variations of these energies and of the molecular geometry with the large-amplitude coordinate. The fitting is aided by results obtained from ab initio calculations we perform on the triangular and linear configurations of the molecule. The current data set is consistent with a large-amplitude potential energy function in which the energy difference between the triangular and linear configurations is 1883 cm−1. The statistical error on this energy difference is 22 cm−1, but we estimate the physical uncertainty to be about 200 cm−1. This result is in excellent agreement with the energy difference of 1819 cm−1 we obtain in our best ab initio calculations. The semirigid bender fitting and our best ab initio calculations are also both consistent with a potential energy function having no local minimum at linearity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.466348
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...