Optical dipole orientation of interlayer excitons in 
MoSe2−WSe2
 heterostacks

<div>Charged droplets play a central role in native mass spectrometry, atmospheric aerosols and in serving as micro-reactors for accelerating chemical reactions. The surface excess charge layer in droplets has often been associated with distinct chemistry. Using molecular simulations for droplets with Na+ and Cl- ions we have found that this layer is ≈ 1.5−1.7 nm thick and depending on the droplet size it includes 33%-55% of the total number of ions. Here, we examine the eﬀect of droplet size and nature of ions in the structure of the surface excess charge layer by using molecular dynamics. We ﬁnd that in the presence of simple ions the thickness of the surface excess charge layer is invariant not only with respect to droplet size but also with respect to the nature of the simple ions and it is not sensitive to ﬁne details of diﬀerent force ﬁelds used in our simulations.</div><div> In the presence of macroions the excess surface charge layer may extend to 2.0. nm. For the same droplet size, iodide and model hydronium ions show considerably higher concentration than the sodium and chloride ions. <br></div><div>We also ﬁnd that diﬀerences in the average water dipole orientation in the presence of cations and anions in this layer are reﬂected in the charge distributions. Within the surface charge layer, the number of hydrogen bonds reduces gradually relative to the droplet interior where the number of hydrogen bonds is on the average 2.9 for droplets of diameter < 4 nm and 3.5 for larger droplets. The decrease in the number of hydrogen bonds from the interior to the surface is less pronounced in larger droplets. In droplets with diameter < 4 nm and high concentration of ions the charge of the ions is not compensated only by the solvent polarization charge but by the total charge that also includes the other free charge. This ﬁnding shows exceptions to the commonly made assumption that the solvent compensates the charge of the ions in solvents with very high dielectric constant. The study provides molecular insight into the bi-layer droplet structure assumed in the equilibrium partitioning model of C. Enke and assesses critical assumptions of the Iribarne-Thomson model for the ion-evaporation mechanism. <br></div>

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Influence of metal phthalocyanine molecular orientation on charge separation at organic donor/acceptor interface

Journal of Materials Chemistry C ◽

10.1039/d0tc04895j ◽

2021 ◽

Author(s):

Heeseon Lim ◽

Sena Yang ◽

Sang-Hoon Lee ◽

Jung-Yong Lee ◽

Yeunhee Lee ◽

...

Keyword(s):

Solar Cell ◽

Charge Separation ◽

Molecular Orientation ◽

Organic Solar Cell ◽

Metal Phthalocyanine ◽

Dipole Orientation ◽

Highly Efficient ◽

Donor Acceptor

To achieve a highly efficient organic solar cell (OPVs), control of molecular orientation is one of prime important factors, for interfacial dipole orientation and energy offset at donor/acceptor (D/A) interface...

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Probing intramolecular vibronic coupling through vibronic-state imaging

Nature Communications ◽

10.1038/s41467-021-21571-z ◽

2021 ◽

Vol 12 (1) ◽

Cited By ~ 1

Author(s):

Fan-Fang Kong ◽

Xiao-Jun Tian ◽

Yang Zhang ◽

Yun-Jie Yu ◽

Shi-Hao Jing ◽

...

Keyword(s):

Single Molecule ◽

Molecular Spectroscopy ◽

Transition Density ◽

Real Space ◽

Vibronic Coupling ◽

Vibronic State ◽

Dipole Orientation ◽

Transition Dipole ◽

Franck Condon ◽

Strong Dynamic

AbstractVibronic coupling is a central issue in molecular spectroscopy. Here we investigate vibronic coupling within a single pentacene molecule in real space by imaging the spatial distribution of single-molecule electroluminescence via highly localized excitation of tunneling electrons in a controlled plasmonic junction. The observed two-spot orientation for certain vibronic-state imaging is found to be evidently different from the purely electronic 0–0 transition, rotated by 90°, which reflects the change in the transition dipole orientation from along the molecular short axis to the long axis. Such a change reveals the occurrence of strong vibronic coupling associated with a large Herzberg–Teller contribution, going beyond the conventional Franck–Condon picture. The emergence of large vibration-induced transition charges oscillating along the long axis is found to originate from the strong dynamic perturbation of the anti-symmetric vibration on those carbon atoms with large transition density populations during electronic transitions.

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Dipole orientation effects on nonlinear optical properties of organic molecular aggregates

The Journal of Chemical Physics ◽

10.1063/1.1565320 ◽

2003 ◽

Vol 118 (18) ◽

pp. 8420-8427 ◽

Cited By ~ 79

Author(s):

Ayan Datta ◽

Swapan K. Pati

Keyword(s):

Optical Properties ◽

Nonlinear Optical ◽

Nonlinear Optical Properties ◽

Molecular Aggregates ◽

Dipole Orientation ◽

Orientation Effects

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Field-induced conformation transition and dipole orientation in poly(vinylidene fluoride)

Polymer Bulletin ◽

10.1007/bf00254376 ◽

1982 ◽

Vol 7 (9-10) ◽

pp. 497-504 ◽

Cited By ~ 9

Author(s):

R. Danz

Keyword(s):

Vinylidene Fluoride ◽

Dipole Orientation ◽

Poly Vinylidene Fluoride ◽

Conformation Transition

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Magnetopause energy transfer dependence on the interplanetary magnetic field and the Earth's magnetic dipole axis orientation

Annales Geophysicae ◽

10.5194/angeo-30-515-2012 ◽

2012 ◽

Vol 30 (3) ◽

pp. 515-526 ◽

Cited By ~ 10

Author(s):

M. Palmroth ◽

R. C. Fear ◽

I. Honkonen

Keyword(s):

Magnetic Field ◽

Energy Transfer ◽

Interplanetary Magnetic Field ◽

Large Data ◽

Seasonal Effect ◽

Dipole Orientation ◽

Data Set ◽

Axis Orientation ◽

Simulation Results ◽

The Imf

Abstract. We examine the spatial variation of magnetospheric energy transfer using a global magnetohydrodynamic (MHD) simulation (GUMICS-4) and a large data set of flux transfer events (FTEs) observed by the Cluster spacecraft. Our main purpose is to investigate whether it is possible to validate previous results on the spatial energy transfer variation from the GUMICS-4 simulation using the statistical occurrence of FTEs, which are manifestations of magnetospheric energy transfer. Previous simulation results have suggested that the energy transfer pattern at the magnetopause rotates according to the interplanetary magnetic field (IMF) orientation, and here we investigate whether a similar rotation is seen in the locations at which FTE signatures are observed. We find that there is qualitative agreement between the simulation and observed statistics, as the peaks in both distributions rotate as a function of the IMF clock angle. However, it is necessary to take into account the modulation of the statistical distribution that is caused by a bias towards in situ FTE signatures being observed in the winter hemisphere (an effect that has previously been predicted and observed in this data set). Taking this seasonal effect into account, the FTE locations support the previous simulation results and confirm the earlier prediction that the energy transfers in the plane of the IMF. In addition, we investigate the effect of the dipole orientation (both the dipole tilt angle and its orientation in the plane perpendicular to the solar wind flow) on the energy transfer spatial distribution. We find that the energy transfer occurs mainly in the summer hemisphere, and that the dayside reconnection region is located asymmetrically about the subsolar position. Finally, we find that the energy transfer is 10% larger at equinox conditions than at solstice, contributing to the discussion concerning the semiannual variation of magnetospheric dynamics (known as "the Russell-McPherron effect").

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