Library

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
Filter
  • 1
    Electronic Resource
    Electronic Resource
    The HeNe interatomic potential from multiproperty fits and Hartree–Fock calculations (1988)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 89 (1988), S. 2866-2880 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: New high-resolution differential scattering cross sections are reported for the HeNe interaction. These experimental results are combined with Hartree–Fock calculations in constructing a highly accurate interatomic potential. The new potential is capable of reproducing all available experimental data judged to be sufficiently reliable. This includes properties that are highly sensitive to the very weak attractive well and its outer bowl, in addition to the weakly repulsive wall. The potential is compared to those previously proposed for HeNe, particularly to one obtained by direct inversion of differential cross section data of similarly high quality. The potential crosses through zero at σ=2.699 A(ring); its minimum occurs at rm=3.029 A(ring) with a depth of ε=1.83 meV.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.454991
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Infrared photodissociation of size-selected methylamine clusters (1991)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 94 (1991), S. 23-29 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Infrared photodissociation spectra of (CH3NH2)n clusters were measured from n=2 to n=6 near the absorption of the C–N stretching mode of the monomer at 1044 cm−1 using a line tunable cw CO2 laser. The clusters are size selected by scattering them from a helium beam. The dimer spectrum shows a double-peak structure with a red- (1038 cm−1) and a blue- (1048 cm−1) shifted peak which is attributed to the nonequivalent position of the C–N in the open dimer structure. The larger clusters exhibit only one peak between 1045.4 and 1046.0 cm−1 which is caused by the equivalent position of the C–N in the cyclic structures of the larger clusters. Calculations of the minimum-energy configurations confirm these results. The linewidth increases by more than a factor of 3 for cold and internally excited dimers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.460382
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Reply to the comment on: "Electron bombardment fragmentation of size selected NH3 clusters'' (1990)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 93 (1990), S. 3726-3727 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The experiments reported in Ref.1 were repeated with size−selected clusters of ammonia. It was concluded from the results of these experiments that the missing ion intensity maxima in ammonia cluster spectra is a cosequence of the cluster size and not, as was stated in Ref.3, of the beam conditions.(AIP)
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.458808
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Photodissociation of oriented HXeI molecules in the gas phase (2001)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 114 (2001), S. 4755-4758 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: We report the first production of the molecule HXeI, which is bound by ionic forces, in the gas phase. The molecule is generated by the photodissociation of HI molecules on a large Xen cluster and is identified by detecting the asymmetric distribution of the H atom fragments of the oriented HXeI. The orientation is achieved in a combined pulsed laser and weak electrostatic field making use of the large anisotropy in the polarizability and the large dipole moment of this molecule. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1354144
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Surface vibrations of large water clusters by helium atom scattering (2000)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 112 (2000), S. 11038-11047 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The low energy intermolecular vibrational modes of water clusters have been measured by high resolution inelastic helium atom scattering. The water clusters are generated in adiabatic expansions through conical nozzles at the mean sizes n¯=22, 80, and 194. By accompanying semiclassical and classical calculations for n=90 the excited mode near 5.1 meV has been identified as O⋅⋅O⋅⋅O bending motion between adjacent hydrogen bonds, involving 3-coordinated water molecules on the amorphous cluster surface. The energy of this mode increases slightly from 4.3 to 5.5 meV with increasing cluster size from n¯=22 to 194 and approaches the results for the dispersionless surface phonons of ice. The cluster temperature determined from the deexcitation is between 69 and 101 K. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.481744
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Intermolecular vibrations of large ammonia clusters from helium atom scattering (2002)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 117 (2002), S. 3149-3159 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The excitation of the low-energy intermolecular modes of ammonia clusters by helium atom scattering has been calculated using classical trajectories. The energy transfer is investigated as a function of scattering angle (from 10° to 90°), collision energy (94.8 and 50.5 meV), cluster size (n=18, 100, 1000), and cluster temperature (Tc=1 K, 30–50 K, and 105 K). It is observed that predominantly the mode at 7 meV and to a lesser extent also the one at 12 meV are excited. These are surface modes that mainly originate from the angular motion of three adjacent N atoms. The excitation is nearly independent of the cluster size and the probability for multiphonon excitation steadily increases with increasing deflection angle. This trend is even strengthened by increasing the collision energy. The role of the cluster temperature is to broaden the energy transfer distribution with increasing values. The calculations are compared with previous and new measurements presented here of the double-differential cross sections (dσ/dω)ΔE of ammonia clusters of average size 〈n〉=92 at two collision energies and 〈n〉=1040 at one energy. While the general trends in the angular and energy dependence could be well reproduced, the correct cluster temperature was crucial in getting good agreement at the lower collision energy for n=100. At the higher collision energy, the large energy transfer is not reproduced, probably a shortcoming of the potential models to account correctly for the anharmonicity of the strong multiquantum excitations. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1494778
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Photodissociation of HBr adsorbed on the surface and embedded in large Arn clusters (2000)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 113 (2000), S. 329-338 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Ultraviolet (UV) photodissociation experiments are carried out for Arn(HBr) clusters in which the HBr is adsorbed on the surface of the Arn, and also on isomers of these systems in which HBr is embedded within the rare-gas cluster. The mean size of the cluster distribution in the experiments is around n¯=130. The kinetic energy distribution (KED) of the hydrogen atoms that left the clusters is measured. Molecular dynamics (MD) simulations of the photodissociation of the chemically similar clusters Arn(HCl) are used to provide a qualitative interpretation of the experimental results. The clusters with embedded HBr give a very cold H-atom KED. The clusters with the surface-adsorbed HBr give a KED with two peaks, one corresponding to very low energy H atoms and the other pertaining to high energies, of the order of 1.35 eV. The theoretical simulations show that already for n=54, there is a strong cage effect for the "embedded" molecule case, resulting in slow H atoms. The surface-adsorbed case is interpreted as due to two types of possible adsorption sites of HX on Ar55: for a locally smooth adsorption site, the cage effect is relatively weak, and hot H atoms emerge. Sites where the HBr is adsorbed at a vacancy of Arn lead to "encapsulation" of the H atom produced, with a strong cage effect. A weak tail of H atoms with energies well above the HBr monomer excess energy is observed for the embedded case. Simulations support that this is due to a second photon absorption by recombined, but still vibrationally hot, HBr. The results throw light on the differences between the cage effect inside bulk structure and at surfaces. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.481798
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Structure of ammonia clusters from n=3 to 18 (2001)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 114 (2001), S. 7848-7852 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Optimized structures and bonding energies have been calculated for ammonia clusters from n=3 to n=18 using a pairwise additive model potential. The trimer and tetramer are stable cyclic configurations. From the pentamer onward the structures are three dimensional with an increasing tendency to amorphous behavior. The exceptions are the heptamer with a Cs axis, the hexadecamer with a central atom, and the very stable and completely symmetric dodecamer with the D6h point group. Here each ammonia molecule is bound by two covalent and two hydrogen bonds. In general, the coordination number increases from 2.0 for the rings over 4.0 for n=12 to 4.2 for n=18. The structures agree where available with previously obtained results for a more elaborate potential. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1365096
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Vibrational spectra of ammonia clusters from n=3 to 18 (2001)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 114 (2001), S. 7853-7858 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: We have calculated the vibrational spectra of the umbrella (ν2), the symmetric (ν1), and the asymmetric (ν3) N–H stretch mode for ammonia clusters from n=3–18. The results are based on recent structure calculations and a molecular perturbation approach that includes the anharmonicities. Clusters with high symmetry exhibit few lines only and show the expected blue shifts for the umbrella and red shifts for the two N–H stretch modes. The calculated frequencies of the umbrella mode agree very well with experimental results for n=2–5 as far as the general shape is concerned, but overestimate the absolute shifts. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1365097
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Experimental evidence for an isomeric transition of size selected methanol hexamers (1994)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 100 (1994), S. 6974-6976 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: We have measured the predicted isomeric transition between the two energetically lowest lying isomers of S6 and C2 symmetry of (CH3OH)6. The clusters are size selected by momentum transfer in collisions with He, and identified by their infrared spectra. The transition occurs at a nozzle temperature of 368 K corresponding to a cluster temperature of 23 K.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.467014
    Library Location Call Number Volume/Issue/Year 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...