scholarly journals Localized Optical Excitations and Two-Exciton Spectroscopy of Phenylacetylene Dendrimers

1998 ◽  
Vol 543 ◽  
Author(s):  
V. Chernyak ◽  
E. Y. Poliakov ◽  
S. Tretiak ◽  
S. Mukamel
Keyword(s):  
Optical Response ◽  
Explicit Calculation ◽  
Two Photon ◽  
Numerical Effort ◽  
Conjugated Dendrimers ◽  
Optical Excitations ◽  
The One ◽  
Photon Spectra ◽  
High Degree ◽  
Exciton Scattering

AbstractThe one- and two-exciton manifolds of conjugated dendrimers possessing fractal geometries are studied using the Frenkel exciton model. Two-photon spectra can be used to determine both the magnitude and the sign of short-range coupling among segments. Self-similarity and the high degree of symmetry make it possible to compute the one-exciton states and the optical response with reduced numerical effort that scales linearly rather than exponentially with the number of generations. The third-order optical response and exciton scattering matrix are expressed in compact forms using irreducible representation of optical excitations, totally avoiding the expensive explicit calculation of two-exciton eigenstates.

A Combined Experimental-Computational Investigation to Uncover the Puzzling (Chiro-)optical Response of Pyridocyclophanes: One- and Two-Photon Spectra

2015 ◽  
Vol 21 (34) ◽  
pp. 12136-12147 ◽  
Author(s):  
Daniele Padula ◽  
Inmaculada R. Lahoz ◽  
Carlos Díaz ◽  
Florencio E. Hernández ◽  
Lorenzo Di Bari ◽  
...  
Keyword(s):  
Optical Response ◽  
Computational Investigation ◽  
Two Photon ◽  
Photon Spectra

Two-photon spectroscopy of the Schiff base of all-trans-retinal. Nature of the low-lying π π* singlet states

1985 ◽  
Vol 63 (7) ◽  
pp. 1967-1971 ◽  
Author(s):  
Lionel P. Murray ◽  
Robert R. Birge
Keyword(s):  
Excitation Spectrum ◽  
Polarized Light ◽  
Wavelength Region ◽  
Photon Absorption ◽  
Two Photon ◽  
Photon Excitation ◽  
The One ◽  
Photon Spectra ◽  
Π State ◽  
Two Photon Excitation

The two-photon excitation spectrum of all-trans-N-retinylidene-n-butylamine (ATRSB) in EPA at 77 K is obtained over the wavelength region from 370 to 455 nm (λex/2) using linearly polarized light. The two-photon excitation maximum is observed at ~422 nm (λex/2) and is red shifted ~2800 cm−1 from the one-photon absorption maximum at ~377 nm. We assign the two-photon excitation spectrum to the "1Ag*−" ← S0 transition which indicates that the "1Ag*−" π π* state lies below the "1Bu*+" π π* state in ATRSB. Comparisons of the one-photon absorption, two-photon excitation, and fluorescence spectra of ATRSB with the corresponding spectra of all-trans-retinal are presented. PPP-CISD calculations correctly predict the directions but not the magnitudes of the blue shifts of the π π* excited state transition energies in going from all-trans-retinal to ATRSB. We postulate that the "1Ag*−" π π* state is preferentially stabilized relative to both the ground state and the nearby "1Bu*+" state by hydrogen bonding to solvent molecules. Comparison of the spectra reported here with the two-photon spectra of rhodopsin provides further evidence that the chromophore in rhodopsin is protonated.

El Prestige: comparativa de los regímenes internacionales de responsabilidad civil

2019 ◽  
Vol 37 (3) ◽  
pp. 31
Author(s):  
Raquel Fernández González ◽  
Marcos Íñigo Pérez Pérez
Keyword(s):  
Institutional Economics ◽  
Geographical Area ◽  
New Institutional Economics ◽  
Rigorous Analysis ◽  
Judicial Process ◽  
Main Research ◽  
Civil Responsibility ◽  
The One ◽  
High Degree ◽  
The Prestige

The return of institutions to the main research agenda has highlighted the importance of rules in economic analysis. The New Institutional Economics has allowed a better understanding of the case studies that concern different areas of knowledge, also the one concerning the management of natural resources. In this article, the institutional analysis focuses on the maritime domain, where two large civil liability regimes for pollution coexist (OPA 90-IMO), each in a different geographical area (United States - Europe). Therefore, a comparative analysis is made between the two large regimes of civil responsibility assignment applying them to the Prestige catastrophe. In this way, the allocation and distribution of responsibilities in the investigation and subsequent judicial process of the Prestige is compared with an alternative scenario in which the applicable compensation instruments are governed by the provisions of the Oil Polution Act of 1990 (OPA 90), in order to establish a rigorous analysis on the effects that the different norms can have in the same scenario. In the comparative established in the case of the Prestige, where the responsibilities were solved very slowly in a judicial process with high transaction costs, the application of rules governed by the OPA 90 would not count with such a high degree of imperfection. This is so, since by applying the preponderance of the evidence existing in OPA 90 there would be no mitigation for the presumed culprits. On the other hand, the agents involved in the sinking would not be limited only to the owner, but also that operators or shipowners would be responsible as well. In addition, the amount of compensation would increase when counting in the damage count the personal damages, the taxes without perceiving and the ecological damage caused in a broad sense, damages not computable in the IMO.

Femtosecond Spectroscopic Studies of the One- and Two-Photon Excited-State Dynamics of 2,2,17,17-Tetramethyloctadeca-5,9,13-trien-3,7,11,15-tetrayne:  A Trimeric Oligodiacetylene

2006 ◽  
Vol 110 (40) ◽  
pp. 11435-11439 ◽  
Author(s):  
Grzegorz M. Balkowski ◽  
Michiel Groeneveld ◽  
Hong Zhang ◽  
Cindy C. J. Hendrikx ◽  
Michael Polhuis ◽  
...  
Keyword(s):  
Excited State ◽  
Spectroscopic Studies ◽  
Excited State Dynamics ◽  
Two Photon ◽  
The One

Theoretical Investigation on the One- and Two-photon Absorption Properties of Porphyrin-thiophene Chromophores

2009 ◽  
Vol 27 (7) ◽  
pp. 1269-1279 ◽  
Author(s):  
Wenchao LI ◽  
Jikang FENG ◽  
Aimin REN ◽  
Xiangbiao ZHANG ◽  
Chiachung SUN
Keyword(s):  
Theoretical Investigation ◽  
Photon Absorption ◽  
Absorption Properties ◽  
Two Photon Absorption ◽  
Two Photon ◽  
The One

Theoretical studies on the one- and two-photon absorption of tetrabenzoporphyrins and phthalocyanines

2004 ◽  
Vol 82 (1) ◽  
pp. 19-26 ◽  
Author(s):  
Xin Zhou ◽  
Ai-Min Ren ◽  
Ji-Kang Feng ◽  
Xiao-Juan Liu
Keyword(s):  
Dipole Moment ◽  
Cross Sections ◽  
Density Functional ◽  
Transition Dipole Moment ◽  
Photon Absorption ◽  
Transition Dipole ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Order Of Magnitude ◽  
The One

The one-photon absorption (OPA) properties of tetrabenzoporphyrins (TBPs) and phthalocyanines (Pcs) were studied using the semiempirical ZINDO method and time-dependent density functional theory (TDDFT), respectively. The compared results confirmed that the semiempirical ZINDO method was reasonably reliable when calculating the OPA of tetrabenzoporphyrins and phthalocyanines. On the basis of the OPA properties obtained from the ZINDO method, two-photon absorption (TPA) properties of two series of molecules were investigated, using ZINDO and sum-over-states (SOS) methods. The results showed that the TPA cross-sections of all molecules were in the range of 220.6 × 10–50 – 345.9 × 10–50 cm4·s·photon–1, which were in the same order of magnitude as the values reported in the literature. The relatively larger δ(ω) value for Pcs with respect to that for corresponding TBPs originates from larger intramolecular charge transfer, which can be characterized by the difference of dipole moment between S0 and S1 and the transition dipole moment between S1 and S5.Key words: two-photon absorption, ZINDO, sum-over-states, tetrabenzoporphyrin, phthalocyanines.

scholarly journals Comparison of a Chaotic Cryptosystem with Other Cryptography Systems

2020 ◽  
Vol 10 (5) ◽  
pp. 6187-6190
Author(s):  
A. S. Alshammari
Keyword(s):  
Stream Cipher ◽  
Security Level ◽  
Brute Force ◽  
Randomness Test ◽  
Symmetric Key ◽  
The One ◽  
Symmetric Key Cryptography ◽  
High Degree

The keyspace of a cryptography system must be long enough in order to protect it from brute force attacks. The One-Time Pad (OTP) encryption is unconditionally secure because of its truly random keystream that is used only once. This paper proposes a new chaotic symmetric cryptosystem approach, comparable to OTP. The proposed system utilizes two Lorenz generators, a main and an auxiliary, where the aim of the second one is to make one of the main Lorenz generator’s parameters to vary continually with time in a chaotic manner. This technique was built on digitizing two Lorenz chaotic models to increase the security level. The scrambling scheme was developed and the Lorenz stream cipher binary stream successfully passed the NIST randomness test. The cryptosystem showed a high degree of security, as it had a keyspace of 2576, and it was compared with existing symmetric key cryptography systems, such as DES, 3DES, AES, Blowfish, and OTP.

scholarly journals The Synthesis of Stochastic Circuits for Nanoscale Computation

2009 ◽  
Vol 1 (4) ◽  
pp. 39-57 ◽  
Author(s):  
Weikang Qian ◽  
John Backes ◽  
Marc D. Riedel
Keyword(s):  
Data Structures ◽  
Self Assembly ◽  
Logic Synthesis ◽  
Nanowire Arrays ◽  
Stochastic Nature ◽  
Symbolic Data ◽  
The One ◽  
High Degree ◽  
Stochastic Circuits ◽  
General Method

Emerging technologies for nanoscale computation such as self-assembled nanowire arrays present specific challenges for logic synthesis. On the one hand, they provide an unprecedented density of bits with a high degree of parallelism. On the other hand, they are characterized by high defect rates. Also they often exhibit inherent randomness in the interconnects due to the stochastic nature of self-assembly. We describe a general method for synthesizing logic that exploits both the parallelism and the random effects. Our approach is based on stochastic computation with parallel bit streams. Circuits are synthesized through functional decomposition with symbolic data structures called multiplicative binary moment diagrams. Synthesis produces designs with randomized parallel components—and operations and multiplexing—that are readily implemented in nanowire crossbar arrays. Synthesis results for benchmarks circuits show that our technique maps circuit designs onto nanowire arrays effectively.

scholarly journals Personal Agency Features of Younger Adolescents with A High Degree Of Passion for Computer Games

2018 ◽  
Vol 7 (3.14) ◽  
pp. 331
Author(s):  
Anna Viktorovna Grishina ◽  
Elena Nikolaevna Volkova
Keyword(s):  
Computer Games ◽  
Self Regulation ◽  
Personal Agency ◽  
Modern Life ◽  
Number Of Children ◽  
The Social ◽  
Computer Club ◽  
Minimum Age ◽  
The One ◽  
High Degree

In the era of intensive informatization of society, computer becomes an integral part of the modern life of the younger teenagers. In Russia, the number of children spending time in front of monitors, playing computer games at home or in a computer club, increases every day. According to Entermedia LLC, the percentage of sales of computer games increases by 50% annually. Currently, 23% of the population of Russia plays computer games, at that the minimum age for a computer player is two years.Strengthening polarization regarding children's interest to computer games becomes one of the most important problems. What is meant here is the fact that, on the one hand, there are adolescents, whose interest in computer games is quite sustainable, while, on the other hand, there are also schoolchildren experiencing mild interest or no interest at all to computer games. The relevance of the present work is determined by the social danger of the phenomenon called high passion for computer games, which deforms, and sometimes blocks the development of the most important personal entities [3, 5, 9, 12, 15]. In this regard, the investigation of the features of personal agency in younger adolescents, which is responsible for the self-regulation of behavior and activity of a subject, is of particular importance. 

Erratum: Two-photon spectra of single-crystal gadolinium diglycolate

1991 ◽  
Vol 44 (14) ◽  
pp. 7769-7769
Author(s):  
Tapanendu Kundu ◽  
Asok K. Banerjee ◽  
Mihir Chowdhury
Keyword(s):  
Single Crystal ◽  
Two Photon ◽  
Photon Spectra
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