A diatomics-in-molecules model for singly ionized neon clusters

Fieber, M.; Ding, A.; Kuntz, P. J.

doi:10.1007/bf01436741

Cited by 20 publications

(8 citation statements)

References 36 publications

(44 reference statements)

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“…The mass of the 20 Ne isotope, m = 19.992 435 6 a.m.u., has been used in this study. 49 The nonadiabatic couplings are calculated using the Hellmann-Feynman formula with analytical calculation of the gradients of the DIM Hamiltonian.…”

Section: E Computational Detailsmentioning

confidence: 99%

“…In addition, a 22 Ne isotope enrichment effect has been shown by Fieber et al 13 and by Scheier and Märk. 16 This has been attributed by Johnson and co-workers 17 to the ion-molecule exchange reaction 22 Ne + 20 Ne 2 + → 20 Ne+ 20 Ne 22 Ne + . From the theoretical point of view, the first studies have concentrated on the determination of the electronic and geometrical equilibrium structure of the neon clusters, in order to interpret the experimental "magic numbers".…”

Section: Introductionmentioning

confidence: 95%

“…This has been confirmed by more recent high level ab initio calculations, which have also proved the accuracy of the diatomics-in-molecules ͑DIM͒ model for these clusters. 19 The structure of Ne n + clusters for n ജ 3 was first studied by Fieber et al 20 using the DIM method. 21 The most recent and accurate results have been obtained by Naumkin and Wales 22 using the DIM method with high level ab initio input diatomic curves.…”

Section: Introductionmentioning

confidence: 99%

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Dissociative ionization of neon clusters Nen, n=3 to 14: A realistic multisurface dynamical study

Bonhommeau

Viel

Halberstadt

2005

The Journal of Chemical Physics

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The molecular dynamics with quantum transitions (MDQT) method is applied to study the fragmentation dynamics of neon clusters following vertical ionization of neutral clusters with 3 to 14 atoms. The motion of the neon atoms is treated classically, while transitions between the adiabatic electronic states of the ionic clusters are treated quantum mechanically. The potential energy surfaces are described by the diatomics-in-molecules model in a minimal basis set consisting of the effective 2p orbitals on each neon atom for the missing electron. The fragmentation mechanism is found to be rather explosive, with a large number of events where several atoms simultaneously dissociate. This is in contrast with evaporative atom by atom fragmentation. The dynamics are highly nonadiabatic, especially at shorter times and for the larger clusters. Initial excitation of the neutral clusters does not affect the fragmentation pattern. The influence of spin-orbit coupling is also examined and found to be small, except for the smaller size systems for which the proportion of the Ne+ fragment is increased up to 43%. From the methodological point of view, most of the usual momentum adjustment methods at hopping events are shown to induce nonconservation of the total nuclear angular momentum because of the nonzero electronic to rotation coupling in these systems. A new method for separating out this coupling and enforcing the conservation of the total nuclear momentum is proposed. It is applied here to the MDQT method of Tully but it is very general and can be applied to other surface hopping methods.

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Section: E Computational Detailsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Dissociative ionization of neon clusters Nen, n=3 to 14: A realistic multisurface dynamical study

Bonhommeau

Viel

Halberstadt

2005

The Journal of Chemical Physics

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“…The following studies mainly focused on the determination of the most stable ionic configurations and of ionic core sizes, using the diatomics-inmolecules ͑DIM͒ model for the potential-energy surfaces. [25][26][27][28][29] They proved that the ionic core of rare-gas clusters was linear and composed of three or four atoms depending on the nature of the rare gas, and sometimes on the cluster size. In particular, a recent work of Gascón et al shows a transition from a triatomic core to a tetra-atomic core for Xe n + clusters when the ionic cluster size evolves from 14 to 19 atoms and the reverse transition when the cluster size evolves from 20 to 25 atoms.…”

Section: Introductionmentioning

confidence: 99%

Modelization of the fragmentation dynamics of krypton clusters (Krn,n=2–11) following electron impact ionization

Bonhommeau

Bouissou

Halberstadt

et al. 2006

The Journal of Chemical Physics

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We present the first prediction for the fragmentation dynamics following electron impact ionization of neutral krypton clusters from 2 to 11 atoms. Fragment proportions and parent ion lifetimes are deduced from a molecular dynamics with quantum transitions study in which the nuclei are treated classically and the transitions between electronic states quantum mechanically. The potential-energy surfaces are derived from a diatomics-in-molecules model to which induced dipole-induced dipole and spin-orbit interactions are added. The results show surprisingly fast and extensive fragmentation for clusters of such a heavy atom, although not as extensive as in the case of neon clusters studied previously [D. Bonhommeau et al., J. Chem. Phys. 123, 54316 (2005)]. The parent ion lifetimes range from 2.8 to 0.7 ps, and the most abundant fragment is Kr(2) (+) for all studied sizes, followed by Kr(+) for sizes smaller than 7 atoms and by Kr(3) (+) for larger sizes. Trimer and larger fragments are found to originate from the lower electronic states of parent ions. The comparison with preliminary results from experiments on size-selected neutral clusters conducted by Steinbach et al. (private communication) reveal a good agreement on the extensive character of the fragmentation. It is checked that the additional internal energy brought by the helium scattering technique used for size selection does not affect the fragment proportions. In addition, the existence of long-lived trajectories is revealed, and they are found to be more and more important for larger cluster sizes and to favor the stabilization of larger fragments. The implications of this work for microsecond-scale dynamics of ionized rare-gas clusters are discussed. In particular, given the extent of fragmentation of the parent clusters and the fast kinetics of the whole process, the small cluster ions that exhibit a monomer loss in the microsecond time window must originate from much larger neutral precursors. The decay rate of the II(12)(u) state of the ionic dimer Kr(2) (+) by spin-orbit coupling is found to be of the order of 3 ps, in contrast to the expected tens of microseconds, but only reasonably faster than the corresponding state of HeNe(+). Finally, the spin-orbit interaction strongly affects both the Kr(+)Kr(2) (+) ratio and some of the characteristic times of the dynamics, especially for smaller sizes, but not the overall dependence of the fragment proportions as a function of cluster size.

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“…Rare gas dimer and trimer ions are supposed to build inner cores of larger rare gas cluster ions. This assumption is strongly evidenced both by experiment 1–3 and theory 4–9. A proper description of the structure and reactivity of the larger clusters is thus highly prerequisited by a detailed knowledge of the diatomic or triatomic cores, including their ro‐vibrational energies.…”

Section: Introductionmentioning

confidence: 99%

Potential energy surface and ro‐vibrational energies of Ne in the ground electronic state

Šindelka

Špirko

Urban³

et al. 2002

Int J of Quantum Chemistry

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ABSTRACT:A global potential energy surface of Ne 3 ϩ in its ground electronic state is evaluated using a Rayleigh-Schrödinger version of the third-order multireference many-body perturbation theory (MR-MBPT) in a complete model space. The ab initio data are fitted quantitatively to a model potential energy function expressed in the Jacobi coordinates, and the fitted function is used to evaluate the ro-vibrational energies of Ne 3 ϩ using the (bond length-bond angle) Sutcliffe-Tennyson (ST) and (hyperspherical) Yamashita-Morokuma-Leforestier (YML) approaches.

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A diatomics-in-molecules model for singly ionized neon clusters

Cited by 20 publications

References 36 publications

Dissociative ionization of neon clusters Nen, n=3 to 14: A realistic multisurface dynamical study

Dissociative ionization of neon clusters Nen, n=3 to 14: A realistic multisurface dynamical study

Modelization of the fragmentation dynamics of krypton clusters (Krn,n=2–11) following electron impact ionization

Potential energy surface and ro‐vibrational energies of Ne in the ground electronic state

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