Charge-transfer-induced evaporation in collisions ofLi312+clusters with Cs atoms (original) (raw)
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Charge transfer dynamics of low energy collisions of Li+ with alkali-covered Cu(001)
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 1993
We present measurements of branching ratios to different final states of the scattered particles for 400 eV Li+ ions incident on alkali-covered Cu(001). In particular, we have measured the charge state fractions and the relative yield of excited states in the scattered flux as a function of the adsorbate-induced work function shift. The results of a resonant charge transfer theory
The Journal of Physical Chemistry A, 2009
The positive and neutral clusters produced by the impact of ∼60 MeV 252 Cf fission fragments on a LiF polycrystalline target are analyzed. The positive ion spectrum is dominated by the (LiF) n Li + series, n ) 0-7, exhibiting a total yield 2 orders of magnitude higher than that of the (LiF) n + series. The yield for the dominant (LiF) n Li + series decreases roughly as exp(-kn), where k ≈ 0.9 for n ) 0-3 and k ≈ 0.6 for the heavier clusters (n ) 4-9), while the yield of the (LiF) n + series also decreases exponentially as n increases with k ≈ 0.6. Theoretical calculations were performed for the (LiF) n Li 0 , (LiF) n Li + , and (LiF) n 0 series for n up to 9. For the smaller clusters the structures first obtained with a genetic algorithm generator were further optimized at the DFT/B3LYP/6-311+G(3df), DFT/B3LYP/LACV3P*, and MP2/LACV3P* levels of theory. An energy criterion is used for a proper taxonomic description of the optimized cluster isomers. Cluster properties such as fragmentation energy and stability are discussed for the proposed configurations. The results show that for all three series the most stable isomers present a linear structure for small cluster size (n ) 1-3), while cubic cells or polyhedral structures are preferred for larger cluster sizes (n ) 4-9). Fragmentation energy results suggest that a desorbed excited (LiF) n Li + ion preferentially dissociates via a cascade of (LiF) n 0 units, in agreement with the slope modification in the exponential decay of the (LiF) n Li + ion abundances for n g 3.
Attractive Xe–Li interaction in Li-decorated clusters
Computational and Theoretical Chemistry, 2013
Xe-binding ability of star-shaped C 5 Li þ 7 cluster and O 2 Li þ 5 super-alkali cluster is studied using the MP2 method. Both C 5 Li þ 7 and O 2 Li þ 5 clusters are found to bind with maximum twelve Xe atoms. We have also studied a series of Li decorated clusters for Xe-binding. All these clusters show good Xe-binding ability. Generally, monocationic clusters have greater binding ability with Xe atoms than the neutral clusters. In addition, a charged Li center binds Xe atoms with better dissociation energy and enthalpy than those with He through Kr. The electron transfer from Xe atoms to Li centers plays a crucial role in binding. The relative contribution of different interaction energy terms towards total interaction energy is analyzed via energy decomposition analysis (EDA). The stability of these Xe-loaded clusters is analyzed in terms of the dissociation energies and reaction enthalpies.
Theoretical and experimental study of the non-stoichiometric Li I (n= 3 and 5) clusters
Chemical Physics Letters, 2013
The neutrals of the Li n I (n = 2-6) clusters were detected using Knudsen-cell which was placed into ionization chamber of the magnetic sector mass spectrometer. The first theoretical and experimental data on the Li 3 I and Li 5 I clusters were presented in this Letter. The ionization energies of the neutral of Li 3 I and Li 5 I clusters, obtained by the electron impact ionization mass spectrometry, were (5.14 ± 0.25) and (4.62 ± 0.25) eV, respectively. We report the geometry, ionization energies and thermodynamical stability of these clusters, calculated at the restricted coupled cluster RHF-RCCSD/cc-pVTZ(Li), cc-pVTZ-PP(I) level of theory.
Nonradiative Energy Transfer in Li*(3p)−CH 4 Collisions
The Journal of Physical Chemistry A, 2002
The direct collisional energy transfer process Li*(3p) + CH 4 f Li*(3s) + CH 4 is investigated both theoretically and experimentally. We measured the nonreactive far-wing absorption profiles of the LiCH 4 complexes by monitoring the Li(3s) f Li(2p) fluorescence at 812.6 nm. The intensity of the Li(3s) f Li(2p) fluorescence decreases with detuning, indicating a more efficient transition rate at low detuning. A high level ab initio calculation in both C 2V and C 3V symmetry is performed to provide a general picture of the nonradiative transition induced by collisions between lithium atoms and a methane molecule.
Energy Transfer in Li*(3p)−H2 Collisions
The Journal of Physical Chemistry A, 2000
The direct collisional energy transfer process Li*(3p) + H 2 f Li*(3s) + H 2 is investigated under gas cell conditions. In particular, we measured the nonreactive far-wing absorption profile of LiH 2 complexes by monitoring the Li(3s) f Li(2p) fluorescence at 812.6 nm. Strong satellite structures are observed at around 700 cm-1 in the blue wing and 162 cm-1 in the red wing of the LiH 2 profile. The experimental results are in agreement with ab initio theoretical predictions, which showed a strong probability of a diabatic transition making the 3p-3s quenching easy.
Microscopic solvation process of single Li atom in small water clusters
Chemical Physics Letters, 1998
y Ž. Ž. We examine the photoelectron spectra of negatively-charged water clusters containing a Li atom, Li H O n (10 , to 2 n reveal the hydration state of the Li atom in water clusters. The 2 Sand 2 P-type transitions of Li are found to be shifted to the lower electron binding energy with increasing cluster size up to n s 4 and then shift back to higher binding energy for n 0 5. We discuss these results in relation to the spontaneous ionization of the Li atom and the formation of two-center ion-pair state, which is a counter part of hydrated electron.
Geometry, electronic properties, and thermodynamics of pure and Al-doped Li clusters
Physical Review B, 2006
The first-principles density functional molecular dynamics simulations have been carried out to investigate the geometric, the electronic, and the finite temperature properties of pure Li clusters ͑Li 10 , Li 12 ͒ and Al-doped Li clusters ͑Li 10 Al, Li 10 Al 2 ͒. We find that the addition of two Al impurities in Li 10 results in a substantial structural change, while the addition of one Al impurity causes a rearrangement of atoms. Introduction of Al impurities in Li 10 establishes a polar bond between Li and nearby Al atom͑s͒, leading to a multicentered bonding, which weakens the Li-Li metallic bonds in the system. These weakened Li-Li bonds lead to a premelting feature to occur at lower temperatures in Al-doped clusters. In Li 10 Al 2 , Al atoms also form a weak covalent bond, resulting in their dimerlike behavior. This causes Al atoms not to "melt" until 800 K, in contrast to the Li atoms which show a complete diffusive behavior above 400 K. Thus, although one Al impurity in Li 10 cluster does not change its melting characteristics significantly, two impurities results in "surface melting" of Li atoms whose motions are confined around an Al dimer.
Journal of Chemical Physics, 2019
Attosecond and femtosecond spectroscopies present opportunities for the control of chemical reaction dynamics and products, as well as for quantum information processing; we address the somewhat unique situation of core-ionization spectroscopy which, for dimeric chromophores, leads to strong valence charge localization and hence tightly paired potential-energy surfaces of very similar shape. Application is made to the quantum dynamics of core-ionized Li 2 +. This system is chosen as Li 2 is the simplest stable molecule facilitating both core ionization and valence ionization. First, the quantum dynamics of some model surfaces are considered, with the surprising result that subtle differences in shape between core-ionization paired surfaces can lead to dramatic differences in the interplay between electronic charge migration and charge transfer induced by nuclear motion. Then, equation-of-motion coupled-cluster calculations are applied to determine potential-energy surfaces for 8 core-excited state pairs, calculations believed to be the first of their type for other than the lowest-energy core-ionized molecular pair. While known results for the lowest-energy pair suggest that Li 2 + is unsuitable for studying charge migration, higher-energy pairs are predicted to yield results showing competition between charge migration and charge transfer. Central is a focus on the application of Hush's 1975 theory for core-ionized X-ray photoelectron spectroscopy to understand the shapes of the potential-energy surfaces and hence predict key features of charge migration.
Energetics and bonding in small lithiated carbon clusters
Journal of Molecular Structure: THEOCHEM, 2007
Small carbon clusters metallized with Li were studied within a hybrid density functional approach with generalized gradient correction. Structures of the ground state and several excited states associated with different isomers and multiplicities were systematically calculated for C x Li y with x = 1-3 and y = 1-5. The most stable isomers are either linear or planar in the ground state. Three-dimensional structures are only identified for CLi 4 , CLi 5 , and C 3 Li 4 . There is important charge transfer in these compounds, showing that ionic bonding is favored as the cluster grows in size. Ionization potentials, electron affinities, and the vibrational analysis of all studied states is provided for all clusters. Structural transitions are predicted for C 2 Li 2 at 1400 K and C 2 Li 4 at 420 K.