Local Field Factors and Dielectric Properties of Liquid Benzene

Abstract

Local electric field factors are calculated for liquid benzene by combining molecular dynamic simulations with a subsequent force-field model based on a combined charge-transfer and point-dipole interaction model for the local field factor. The local field factor is obtained as a linear response of the local field to an external electric field, and the response is calculated at frequencies through the first absorption maximum. It is found that the largest static local field factor is around 2.4, while it is around 6.4 at the absorption frequency. The linear susceptibility, the dielectric constant, and the first absorption maximum of liquid benzene are also studied. The electronic contribution to the dielectric constant is around 2.3 at zero frequency, in good agreement with the experimental value around 2.2, while it increases to 6.3 at the absorption frequency. The π → π* excitation energy is around 6.0 eV, as compared to the gas-phase value of around 6.3 eV, while the experimental values are 6.5 and 6.9 eV for the liquid and gas phase, respectively, demonstrating that the gas-to-liquid shift is well-described.

Pre-breakdown phenomena in hydrocarbon liquids in a point-plane gap under step voltage. Part 2: behaviour under negative polarity and comparison with positive polarity

“…are greatly diminished [42][43][44]. The field strength shown in figure 18(b) is the local field around the molecule that is higher than the macroscopic field of figure 18(a) by a factor of 2-10 depending on the type of molecules in the liquid [45]. This indicates that while the macroscopic field might not be high enough to significantly influence the ionization level or cause removal of excited states, the local field may very well be.…”

Vibrational Stark Effects of Carbonyl Probes Applied to Reinterpret IR and Raman Data for Enzyme Inhibitors in Terms of Electric Fields at the Active Site

“…The observed range, f = 1.6–2.6 based on the differences in slopes of the field-frequency calibration curves ($\mid \Delta {\overrightarrow{\mu }}_{C=O}\mid$) relative to the experimentally measured linear Stark tuning rates ($\mid \Delta {\overrightarrow{\mu }}_{C=O}\mid f$; Table S2), suggests that $\mid \Delta {\overrightarrow{\mu }}_{C=O}\mid$ is approximately half that measured by vibrational Stark spectroscopy, that is f ≈ 2, consistent with earlier work and recent calculations. 1, 3, 53 On the other hand, there may be subtle but systematic discrepancies in the simulations of solute-solvent pairs that are not accounted for at the current level of approximation. This uncertainty makes quantitative comparison between probes difficult, but a single probe can be used consistently to study a system of interest using the VSE.…”

“…2, 52 While the exact value of the local field factor is not known, it is expected to have a value between 1 and 2. 1, 4, 23, 53 As such, the Stark tuning rates are reported in terms of $\mid \Delta {\overrightarrow{\mu }}_{\mathrm{italicprobe}}\mid f$ and this is discussed in detail with the results.…”

Orientation correlation and local field in liquid nitrobenzene

“…45 The maximum ion-induced HRS intensities, obtained from Eqs. (15) and (16) in the limit as θ s → 0 and K D → ∞, are…”

“…4is to obtain the liquid dielectric properties from a molecular dynamics (MD) simulation including the explicit molecular details for the system of interest. [16][17][18][19][20][21][22][23][24][25][26] Such MD simulations have become feasible for systems ranging from simple polar liquids to protein molecules and larger biomolecular systems. [27][28][29][30][31][32] Electrostatic interactions often control the behaviour of complex, heterogeneous systems, but may be poorly represented by continuum model results.…”