A New Interpretation of the Absorption and the Dual Fluorescence of Prodan in Solution

Author(s):  
Cintia Vequi-Suplicy ◽  
Yoelvis Orozco-González ◽  
M. Teresa Lamy ◽  
Sylvio Canuto ◽  
Kaline Coutinho

Prodan is a fluorescent probe used to monitor biological systems such as lipid membrane,<br>proteins and DNA. Remarkable interest is associated to the interpretation of its fluorescent spectrum.<br>In this paper the sequential hybrid Quantum Mechanics/Molecular Mechanics (S-QM/MM) method was used to establish that the fluorescent emission occurs from two different excited states, resulting in a broad asymmetric emission spectrum with two transitions. The absorption spectra in several solvents were measured and calculated using different theoretical models and they all agree that the first observed band is composed of three electronic excitation very close energetically to each other.

2020 ◽  
Author(s):  
Cintia Vequi-Suplicy ◽  
Yoelvis Orozco-González ◽  
M. Teresa Lamy ◽  
Sylvio Canuto ◽  
Kaline Coutinho

Prodan is a fluorescent probe used to monitor biological systems such as lipid membrane,<br>proteins and DNA. Remarkable interest is associated to the interpretation of its fluorescent spectrum.<br>In this paper the sequential hybrid Quantum Mechanics/Molecular Mechanics (S-QM/MM) method was used to establish that the fluorescent emission occurs from two different excited states, resulting in a broad asymmetric emission spectrum with two transitions. The absorption spectra in several solvents were measured and calculated using different theoretical models and they all agree that the first observed band is composed of three electronic excitation very close energetically to each other.


2020 ◽  
Author(s):  
Cintia Vequi-Suplicy ◽  
Yoelvis Orozco-González ◽  
M. Teresa Lamy ◽  
Sylvio Canuto ◽  
Kaline Coutinho

Prodan is a fluorescent probe used to monitor biological systems such as lipid membrane,<br>proteins and DNA. Remarkable interest is associated to the interpretation of its fluorescent spectrum.<br>In this paper the sequential hybrid Quantum Mechanics/Molecular Mechanics (S-QM/MM) method was used to establish that the fluorescent emission occurs from two different excited states, resulting in a broad asymmetric emission spectrum with two transitions. The absorption spectra in several solvents were measured and calculated using different theoretical models and they all agree that the first observed band is composed of three electronic excitation very close energetically to each other.


Author(s):  
Tian Lu ◽  
Qinxue Chen ◽  
Zeyu Liu

Although cyclo[18]carbon has been theoretically and experimentally investigated since long time ago, only very recently it was prepared and directly observed by means of STM/AFM in condensed phase (Kaiser et al., <i>Science</i>, <b>365</b>, 1299 (2019)). The unique ring structure and dual 18-center π delocalization feature bring a variety of unusual characteristics and properties to the cyclo[18]carbon, which are quite worth to be explored. In this work, we present an extremely comprehensive and detailed investigation on almost all aspects of the cyclo[18]carbon, including (1) Geometric characteristics (2) Bonding nature (3) Electron delocalization and aromaticity (4) Intermolecular interaction (5) Reactivity (6) Electronic excitation and UV/Vis spectrum (7) Molecular vibration and IR/Raman spectrum (8) Molecular dynamics (9) Response to external field (10) Electron ionization, affinity and accompanied process (11) Various molecular properties. We believe that our full characterization of the cyclo[18]carbon will greatly deepen researchers' understanding of this system, and thereby help them to utilize it in practice and design its various valuable derivatives.


Author(s):  
Tian Lu ◽  
Qinxue Chen ◽  
Zeyu Liu

Although cyclo[18]carbon has been theoretically and experimentally investigated since long time ago, only very recently it was prepared and directly observed by means of STM/AFM in condensed phase (Kaiser et al., <i>Science</i>, <b>365</b>, 1299 (2019)). The unique ring structure and dual 18-center π delocalization feature bring a variety of unusual characteristics and properties to the cyclo[18]carbon, which are quite worth to be explored. In this work, we present an extremely comprehensive and detailed investigation on almost all aspects of the cyclo[18]carbon, including (1) Geometric characteristics (2) Bonding nature (3) Electron delocalization and aromaticity (4) Intermolecular interaction (5) Reactivity (6) Electronic excitation and UV/Vis spectrum (7) Molecular vibration and IR/Raman spectrum (8) Molecular dynamics (9) Response to external field (10) Electron ionization, affinity and accompanied process (11) Various molecular properties. We believe that our full characterization of the cyclo[18]carbon will greatly deepen researchers' understanding of this system, and thereby help them to utilize it in practice and design its various valuable derivatives.


2007 ◽  
Vol 3 (1) ◽  
pp. 65-69 ◽  
Author(s):  
V.N. Glushkov

A singe Slater determinant consisting of restricted and unrestricted, in spins, parts is proposed to construct a reference configuration for singlet excited states having the same symmetry as the ground one. A partially restricted Hartree-Fock approach is developed to derive amended equations determining the spatial molecular orbitals for singlet excited states. They present the natural base to describe the electron correlation in excited states using the wellestablished spin-annihilated perturbation theories. The efficiency of the proposed method is demonstrated by calculations of electronic excitation energies for the Be atom and LiH molecule.


Author(s):  
Matt Jones

A primary goal in recent research on contextuality has been to extend this concept to cases of inconsistent connectedness, where observables have different distributions in different contexts. This article proposes a solution within the framework of probabi- listic causal models, which extend hidden-variables theories, and then demonstrates an equivalence to the contextuality-by-default (CbD) framework. CbD distinguishes contextuality from direct influences of context on observables, defining the latter purely in terms of probability distributions. Here, we take a causal view of direct influences, defining direct influence within any causal model as the probability of all latent states of the system in which a change of context changes the outcome of a measurement. Model-based contextuality (M-contextuality) is then defined as the necessity of stronger direct influences to model a full system than when considered individually. For consistently connected systems, M-contextuality agrees with standard contextuality. For general systems, it is proved that M-contextuality is equivalent to the property that any model of a system must contain ‘hidden influences’, meaning direct influences that go in opposite directions for different latent states, or equivalently signalling between observers that carries no information. This criterion can be taken as formalizing the ‘no-conspiracy’ principle that has been proposed in connection with CbD. M-contextuality is then proved to be equivalent to CbD-contextuality, thus providing a new interpretation of CbD-contextuality as the non-existence of a model for a system without hidden direct influences. This article is part of the theme issue ‘Contextuality and probability in quantum mechanics and beyond’.


2020 ◽  
Vol 8 (7) ◽  
pp. 2442-2450 ◽  
Author(s):  
Jingjing Yang ◽  
Xing Liu ◽  
Zemei Liu ◽  
Long Wang ◽  
Jing Sun ◽  
...  

Dual emission of a blue fluorescent material and its application in WOLEDs and as a fluorescent probe are investigated.


Fluids ◽  
2019 ◽  
Vol 4 (2) ◽  
pp. 96 ◽  
Author(s):  
Georgi Gary Rozenman ◽  
Shenhe Fu ◽  
Ady Arie ◽  
Lev Shemer

We present the theoretical models and review the most recent results of a class of experiments in the field of surface gravity waves. These experiments serve as demonstration of an analogy to a broad variety of phenomena in optics and quantum mechanics. In particular, experiments involving Airy water-wave packets were carried out. The Airy wave packets have attracted tremendous attention in optics and quantum mechanics owing to their unique properties, spanning from an ability to propagate along parabolic trajectories without spreading, and to accumulating a phase that scales with the cubic power of time. Non-dispersive Cosine-Gauss wave packets and self-similar Hermite-Gauss wave packets, also well known in the field of optics and quantum mechanics, were recently studied using surface gravity waves as well. These wave packets demonstrated self-healing properties in water wave pulses as well, preserving their width despite being dispersive. Finally, this new approach also allows to observe diffractive focusing from a temporal slit with finite width.


2016 ◽  
Vol 71 (3) ◽  
pp. 195-212
Author(s):  
H. Dieter Zeh

AbstractThis is an attempt of a non-technical but conceptually consistent presentation of quantum theory in a historical context. While the first part is written for a general readership, Section 5 may appear a bit provocative to some quantum physicists. I argue that the single-particle wave functions of quantum mechanics have to be correctly interpreted as field modes that are “occupied once” (i.e. first excited states of the corresponding quantum oscillators in the case of boson fields). Multiple excitations lead to apparent many-particle wave functions, while the quantum states proper are defined by wave function(al)s on the “configuration” space of fundamental fields, or on another, as yet elusive, fundamental local basis.


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