Thermal effects on the electric deflection of toluene molecules

Carrera, A.; Mobbili, Marcos Daniel; Moriena, Gustavo; Marceca, Ernesto

doi:10.1016/j.cplett.2008.11.007

Cited by 7 publications

(11 citation statements)

References 17 publications

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“…Here this procedure yielded a rotational temperature of 6 K (with an estimated uncertainty of ± 2 6 K) which is a reasonable choice for supersonic molecular beams with a nozzle temperature of 33 K (for further experimental evidence see the Supporting Information). This temperature was used for all presented simulations. ,, …”

Section: Methodsmentioning

confidence: 99%

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Bismuth-Doped Tin Clusters: Experimental and Theoretical Studies of Neutral Zintl Analogues

Heiles

Johnston

2012

J. Phys. Chem. A

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The electron count of gas-phase clusters is increased gradually by element substitution in order to mimic the total number of electrons of known stable closo-clusters. A combination of elements from the fourth and fifth group of the periodic table such as Sn and Bi is well-suited for this approach. Hence, these small Sn-Bi clusters are investigated by employing the electric field deflection method. For clusters in the series Sn(M-N)Bi(N) (M = 5-13, N = 1-2), the beam profiles obtained in cryogenic experiments are dominated by beam broadening, indicating the presence of a permanent electric dipole moment that is sensitive to the (rigid) cluster structure. An intensive search for the global minimum structure employing a density functional theory/genetic algorithm method is performed. Dielectric properties for the identified low-energy isomers are computed. The structural and dielectric properties are used in beam profile simulations in order to discuss the experimental data. Comparison of theoretical and experimental results enables identification of the growing pattern of these small bimetallic clusters. For multiply doped clusters, it is concluded that the dopant atoms do not form direct Bi-Bi bonds, but more interestingly, a rearrangement of the cluster skeleton becomes apparent. The structural motifs are different from pure tin clusters but rather are rationalized using the corresponding structures of tin anions or are based on the Wade-Mingos concept. Further evidence for this idea is deduced from nuclear independent chemical shift calculations, which show nearly identical behavior for negatively charged pure and neutral bimetallic clusters. All of these findings are consistent with the idea of neutral Zintl analogues in the gas phase.

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Section: Methodsmentioning

confidence: 99%

“…This temperature was used for all presented simulations. 22,24,48 All calculations and simulations were performed on the University of Birmingham's BlueBEAR high-performance computer. 49 ■ RESULTS AND DISCUSSION Doping a tin cluster with bismuth atoms increases the valence electron number successively.…”

Section: ■ Introductionmentioning

confidence: 99%

Bismuth-Doped Tin Clusters: Experimental and Theoretical Studies of Neutral Zintl Analogues

Heiles

Johnston

2012

J. Phys. Chem. A

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“…The molecular beam apparatus used to carry out the experiments has been described in detail elsewhere. , Here, we will present a brief summary of the main components of the machine and give a short explanation of the ED technique used to determine the effective polarizability of the particles. Sodium-doped ammonia clusters were prepared using a pick-up arrangement , in which, first, (NH 3 ) n clusters are generated by a pulsed supersonic expansion of a 5% NH 3 –He gaseous mixture at a pressure of 1 bar, and after that, attachment of one sodium atom occurs as the clusters pass through a collision cell having about 8 × 10 –4 mbar of sodium vapor.…”

Section: Methodsmentioning

confidence: 99%

“…The procedure used to determine the propagation speed of the clusters, v y , was successfully applied previously to other systems. , All the experiments were carried out close to the front of the supersonic beam pulse where a very small velocity spread was found and v y showed no size dependence to our experimental resolution. The measured value for v y was 1480 ± 43 m/s.…”

Section: Methodsmentioning

confidence: 99%

Electric Deflection of Middle-Size Ammonia Clusters Containing (e^–, Na⁺) Pairs

Carrera

Marceca

2015

J. Phys. Chem. A

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Effective polarizabilities of Na(NH3)n (n = 8-27) clusters were measured by electric deflection as a function of the particle size. A significant field-induced shift of the beam intensity profile without the occurrence of broadening revealed that the clusters behave as liquidlike polar objects in the conditions of the experiment (cluster temperatures were estimated in the range of 110-145 K). Most of the cluster polarity is attributed to the spontaneous promotion of the alkali atom valence electron to a diffuse state stabilized by the cluster solvent field, with the consequent formation of (e(-), Na(+)) pairs. The average modulus of the dipole of Na-NH3 clusters, μ0, was determined using the Langevin-Debye theory, and the data was compared with previous measurements obtained for Na-H2O clusters. Sodium-doped ammonia clusters exhibit much larger μ0 values and a step size dependence which is not present when the solvent is water. This evidence suggests that while the (e(-), Na(+)) structure is rather compact in Na(H2O)n clusters and remains almost unchanged during the solvation process, in Na(NH3)n the unpaired electron abandons the proximity of the Na(+) ion and gradually extends and occupies new solvent shells.

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“…To correlate the observed dielectric behaviour to the geometric structure of the cluster, we tried to model the deflection behaviour by molecular dynamic (MD) simulations first introduced by Dugourd et al 45 in order to analyse the beam profiles of asymmetric rotors. 46,47 For that purpose theoretically predicted isomer structures and the dielectric properties are taken into account. The moments of inertia and the electric dipole moment of one isomer structure are used to numerically solve the classical equations of motion for a rigid body, i.e.…”

Section: B Deflection Experimentsmentioning

confidence: 99%