642,844 research outputs found
Ion-induced nucleation. II. Polarizable multipolar molecules
Density functional theory is applied to ion-induced nucleation of polarizable multipolar molecules. The asymmetric nature of the ion-molecule interaction is shown to cause the sign preference in ion-induced nucleation. When the ion-molecule interaction is weak, the observed sign preference is consistent with that of the bare ion-molecule interaction potential and decreases with increasing supersaturation. However, as the ion-molecule interaction becomes stronger, the sign preference in the reversible work exhibits some nontrivial behavior. For molecular parameters applicable for CS2 and CH4, the predicted values of the reversible work of nucleation depend on the sign of the ion charge, yielding a difference in the nucleation rate by factors of 10 to 10^(2) and 10 to 10^(5), respectively
Rydberg atom mediated polar molecule interactions: a tool for molecular-state conditional quantum gates and individual addressability
We study the possibility to use interaction between a polar molecule in the
ground electronic and vibrational state and a Rydberg atom to construct
two-qubit gates between molecular qubits and to coherently control molecular
states. A polar molecule within the electron orbit in a Rydberg atom can either
shift the Rydberg state, or form Rydberg molecule. Both the atomic shift and
the Rydberg molecule states depend on the initial internal state of the polar
molecule, resulting in molecular state dependent van der Waals or dipole-dipole
interaction between Rydberg atoms. Rydberg atoms mediated interaction between
polar molecules can be enhanced up to times. We describe how the
coupling between a polar molecule and a Rydberg atom can be applied to coherent
control of molecular states, specifically, to individual addressing of
molecules in an optical lattice and non-destructive readout of molecular
qubits
Influence of antisymmetric exchange interaction on quantum tunneling of magnetization in a dimeric molecular magnet Mn6
We present magnetization measurements on the single molecule magnet Mn6,
revealing various tunnel transitions inconsistent with a giant-spin
description. We propose a dimeric model of the molecule with two coupled spins
S=6, which involves crystal-field anisotropy, symmetric Heisenberg exchange
interaction, and antisymmetric Dzyaloshinskii-Moriya exchange interaction. We
show that this simplified model of the molecule explains the experimentally
observed tunnel transitions and that the antisymmetric exchange interaction
between the spins gives rise to tunneling processes between spin states
belonging to different spin multiplets.Comment: 5 pages, 4 figure
Directionality in van der Waals Interactions: the Case of 4-Acetylbiphenyl Adsorbed on Au(111)
We report on a theoretical study of adsorption of 4-Acetylbiphenyl molecule
and its diffusion properties in the main directions of the Au(111) surface.
Structural changes of the molecule, which are induced by adsorption lead to
stronger conjugation of the -system. The molecule is adsorbed in a flat
configuration on the surface with roughly the same binding energy along the
[110] and [112] directions, in good agreement with experiments. Furthermore,
the diffusion barriers imply an important directionality of the
molecule-surface interactions. This is somewhat surprising because our
calculations show that the prevailing interaction is the long-range
molecule-surface van der Waals interaction. Despite of its weakness, the van
der Waals interaction discriminates the preferential adsorption sites as well
as imposes a molecular geometry that needs to be considered when rationalizing
the diffusion barriers
Homogeneous reactions of hydrocarbons, silane, and chlorosilanes in radiofrequency plasmas at low pressures
The ion-molecule and radical-molecule mechanisms are responsible for the dissociation of hydrocarbon, silane, and chlorosilane monomers and the formation of polymerized species, respectively, in an RF plasma discharge. In a plasma containing a mixture of monomer and argon the rate-determining step for both dissociation and polymerization is governed by an ion-molecule type of interaction. Adding hydrogen or ammonia to the monomer-argon mixture transforms the rate-determining step from an ion-molecule interaction to a radical-molecule interaction for both monomer dissociation and polymerization
Current induced light emission and light induced current in molecular tunneling junctions
The interaction of metal-molecule-metal junctions with light is considered
within a simple generic model. We show, for the first time, that light induced
current in unbiased junctions can take place when the bridging molecule is
characterized by a strong charge-transfer transition. The same model shows
current induced light emission under potential bias that exceeds the molecular
excitation energy. Results based on realistic estimates of molecular-lead
coupling and molecule-radiation field interaction suggest that both effects
should be observable.Comment: 5 pages, 3 figures, RevTeX
Dynamical Casimir-Polder interaction between a chiral molecule and a surface
We develop a dynamical approach to study the Casimir-Polder force between a
initially bare molecule and a magnetodielectric body at finite temperature.
Switching on the interaction between the molecule and the field at a particular
time, we study the resulting temporal evolution of the Casimir-Polder
interaction. The dynamical self-dressing of the molecule and its
population-induced dynamics are accounted for and discussed. In particular, we
find that the Casimir-Polder force between a chiral molecule and a perfect
mirror oscillates in time with a frequency related to the molecular transition
frequency, and converges to the static result for large times.Comment: 10 pages, 4 figure
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