Dipole Orientation Dependent Symmetry Reduction of Chloroaluminum Phthalocyanine on Cu(111)

2013 ◽  
Vol 117 (2) ◽  
pp. 1013-1019 ◽  
Author(s):  
Tianchao Niu ◽  
Miao Zhou ◽  
Jialin Zhang ◽  
Yuanping Feng ◽  
Wei Chen
Keyword(s):  
Symmetry Reduction ◽  
Dipole Orientation ◽  
Chloroaluminum Phthalocyanine

Molecular Characterization of the Surface Excess Charge Layer in Droplets

2020 ◽  
Author(s):  
Victor Kwan ◽  
Styliani Consta
Keyword(s):  
Hydrogen Bonds ◽  
Surface Charge ◽  
Droplet Size ◽  
Chloride Ions ◽  
Total Charge ◽  
Excess Charge ◽  
Surface Excess ◽  
High Concentration ◽  
Dipole Orientation ◽  
Charge Layer

<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>

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

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...

scholarly journals Probing intramolecular vibronic coupling through vibronic-state imaging

2021 ◽  
Vol 12 (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.

scholarly journals A Hypothesis for Self-Organization and Symmetry Reduction in the Synchronization of Organ-Level Contractions in the Human Uterus during Labor

Symmetry ◽  
2015 ◽  
Vol 7 (4) ◽  
pp. 1981-1988 ◽  
Author(s):  
David Banney ◽  
Roger Young ◽  
Jonathan Paul ◽  
Mohammad Imtiaz ◽  
Roger Smith
Keyword(s):  
Symmetry Reduction ◽  
Self Organization ◽  
Human Uterus ◽  
Organ Level
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