Role of coherent nuclear motion in the ultrafast intersystem crossing of ruthenium complexes

2020 ◽  
Vol 22 (44) ◽  
pp. 25811-25818
Author(s):  
JunWoo Kim ◽  
Dong-gu Kang ◽  
Sang Kyu Kim ◽  
Taiha Joo
Keyword(s):  
Symmetry Breaking ◽  
Wave Packets ◽  
Ruthenium Complexes ◽  
Nuclear Motion ◽  
Intersystem Crossing ◽  
Vibrational Modes ◽  
Time Resolved ◽  
Strongly Coupled ◽  
Metal Ligand

Ultrafast intersystem crossing (ISC) of ruthenium complexes is time-resolved directly. Coherent nuclear wave packets suggest that metal–ligand stretching or symmetry breaking vibrational modes are strongly coupled with the ISC.

scholarly journals Time-resolved high harmonic spectroscopy of dynamical symmetry breaking in bi-circular laser fields: the role of Rydberg states

2017 ◽  
Vol 25 (19) ◽  
pp. 22880 ◽  
Author(s):  
Álvaro Jiménez-Galán ◽  
Nickolai Zhavoronkov ◽  
Marcel Schloz ◽  
Felipe Morales ◽  
Misha Ivanov
Keyword(s):  
Symmetry Breaking ◽  
High Harmonic ◽  
Rydberg States ◽  
Dynamical Symmetry ◽  
Laser Fields ◽  
Time Resolved ◽  
Dynamical Symmetry Breaking

Centrosome Aurora A gradient ensures single polarity axis in C. elegans embryos

2020 ◽  
Vol 48 (3) ◽  
pp. 1243-1253 ◽  
Author(s):  
Sukriti Kapoor ◽  
Sachin Kotak
Keyword(s):  
Symmetry Breaking ◽  
Cell Fate ◽  
Cell Cortex ◽  
Axis Formation ◽  
Aurora A Kinase ◽  
Aurora A ◽  
C Elegans ◽  
Cell Embryo ◽  
Polarity Establishment

Cellular asymmetries are vital for generating cell fate diversity during development and in stem cells. In the newly fertilized Caenorhabditis elegans embryo, centrosomes are responsible for polarity establishment, i.e. anterior–posterior body axis formation. The signal for polarity originates from the centrosomes and is transmitted to the cell cortex, where it disassembles the actomyosin network. This event leads to symmetry breaking and the establishment of distinct domains of evolutionarily conserved PAR proteins. However, the identity of an essential component that localizes to the centrosomes and promotes symmetry breaking was unknown. Recent work has uncovered that the loss of Aurora A kinase (AIR-1 in C. elegans and hereafter referred to as Aurora A) in the one-cell embryo disrupts stereotypical actomyosin-based cortical flows that occur at the time of polarity establishment. This misregulation of actomyosin flow dynamics results in the occurrence of two polarity axes. Notably, the role of Aurora A in ensuring a single polarity axis is independent of its well-established function in centrosome maturation. The mechanism by which Aurora A directs symmetry breaking is likely through direct regulation of Rho-dependent contractility. In this mini-review, we will discuss the unconventional role of Aurora A kinase in polarity establishment in C. elegans embryos and propose a refined model of centrosome-dependent symmetry breaking.

The Role of Interface Vibrational Modes in Thermal Boundary Resistance

2021 ◽  
Author(s):  
Christopher M. Stanley ◽  
Benjamin K. Rader ◽  
Braxton H. D. Laster ◽  
Mahsa Servati ◽  
Stefan K. Estreicher
Keyword(s):  
Boundary Resistance ◽  
Thermal Boundary Resistance ◽  
Vibrational Modes

scholarly journals The role of spin in the degradation of organic photovoltaics

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ivan Ramirez ◽  
Alberto Privitera ◽  
Safakath Karuthedath ◽  
Anna Jungbluth ◽  
Johannes Benduhn ◽  
...  
Keyword(s):  
Transient Absorption ◽  
Bulk Heterojunction ◽  
Critical Factor ◽  
Model Systems ◽  
Transient Absorption Spectroscopy ◽  
Triplet States ◽  
Paramagnetic Resonance ◽  
Time Resolved ◽  
A Charge

AbstractStability is now a critical factor in the commercialization of organic photovoltaic (OPV) devices. Both extrinsic stability to oxygen and water and intrinsic stability to light and heat in inert conditions must be achieved. Triplet states are known to be problematic in both cases, leading to singlet oxygen production or fullerene dimerization. The latter is thought to proceed from unquenched singlet excitons that have undergone intersystem crossing (ISC). Instead, we show that in bulk heterojunction (BHJ) solar cells the photo-degradation of C60 via photo-oligomerization occurs primarily via back-hole transfer (BHT) from a charge-transfer state to a C60 excited triplet state. We demonstrate this to be the principal pathway from a combination of steady-state optoelectronic measurements, time-resolved electron paramagnetic resonance, and temperature-dependent transient absorption spectroscopy on model systems. BHT is a much more serious concern than ISC because it cannot be mitigated by improved exciton quenching, obtained for example by a finer BHJ morphology. As BHT is not specific to fullerenes, our results suggest that the role of electron and hole back transfer in the degradation of BHJs should also be carefully considered when designing stable OPV devices.

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