scholarly journals Two-photon absorption and two-photon circular dichroism of hexahelicene derivatives: a study of the effect of the nature of intramolecular charge transfer

RSC Advances ◽  
2015 ◽  
Vol 5 (23) ◽  
pp. 17429-17437 ◽  
Author(s):  
Carlos Díaz ◽  
Yuly Vesga ◽  
Lorenzo Echevarria ◽  
Irena G. Stará ◽  
Ivo Starỳ ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Charge Transfer ◽  
Intramolecular Charge Transfer ◽  
Photon Absorption ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Electronic Delocalization ◽  
Circular Dichroïsm

Effect of the strength and nature of the extension of the π-electronic delocalization on TPA and TPCD of helicenes derivatives.

scholarly journals Tuning of Hyperpolarizability, One- and Two-Photon Absorption of D-A and D-A-A Type Intramolecular Charge Transfer Based Sensors

2019 ◽  
Author(s):  
Pralok K. Samanta ◽  
Md Mehboob Alam ◽  
Ramprasad Misra ◽  
Swapan K. Pati
Keyword(s):  
Charge Transfer ◽  
Gas Phase ◽  
Density Functional ◽  
Intramolecular Charge Transfer ◽  
Photon Absorption ◽  
First Hyperpolarizability ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Nlo Response ◽  
Donor Acceptor

Solvents play an important role in shaping the intramolecular charge transfer (ICT) properties of π-conjugated molecules, which in turn can affect their one-photon absorption (OPA) and two-photon absorption (TPA) as well as the static (hyper)polarizabilities. Here, we study the effect of solvent and donor-acceptor arrangement on linear and nonlinear optical (NLO) response properties of two novel ICT-based fluorescent sensors, one consisting of hemicyanine and dimethylaniline as electron withdrawing and donating groups (molecule 1), respectively and its boron-dipyrromethene (BODIPY, molecule 2)-fused counterpart (molecule 3). Density functional theoretical (DFT) calculations using long-range corrected CAM-B3LYP and M06-2X functionals, suitable for studying properties of ICT molecules, are employed to calculate the desired properties. The dipole moment (µ) as well as the total first hyperpolarizability (β<sub>total</sub>) of the studied molecules in the gas phase is dominantly dictated by the component in the direction of charge transfer. The ratios of vector component of first hyperpolarizability (β<sub>vec</sub>) to β<sub>total</sub> also reveal unidirectional charge transfer process. The properties of the medium significantly affect the OPA, hyperpolarizability and TPA properties of the studied molecules. Time dependent DFT (TDDFT) calculations suggest interchanging between two lowest excited states of molecule 3 from the gas phase to salvation. The direction of charge polarization and dominant transitions among molecular orbitals involved in the OPA and TPA processes are studied. The results presented are expected to be useful in tuning the NLO response of many ICT-based chromophores, especially those with BODIPY acceptors.<br>

scholarly journals Межзонный двухфотонный линейно-циркулярный дихроизм в полупроводниках в приближении Кейна

2022 ◽  
Vol 56 (1) ◽  
pp. 61
Author(s):  
В.Р. Расулов ◽  
Р.Я. Расулов ◽  
Б.Б. Ахмедов ◽  
И.А. Муминов
Keyword(s):  
Circular Dichroism ◽  
Photon Absorption ◽  
Degree Of Polarization ◽  
Optical Transitions ◽  
Narrow Gap ◽  
Two Photon Absorption ◽  
Narrow Gap Semiconductors ◽  
Two Photon ◽  
Absorption Of Light ◽  
Circular Dichroïsm

Interband two-photon optical transitions are classified and expressions are obtained for the matrix elements in a narrow-gap semiconductor depending on the band parameters, degree of polarization, and light frequency. It is shown that the main contribution to two-photon linear-circular dichroism in narrow-gap semiconductors is made by optical transitions proceeding from the subband of light holes to the conduction band. The dependences of the partial coefficients of interband two-photon absorption of light, which differ from each other by the types of optical transitions, are analyzed depending on the degree of polarization of the light, and a quantitative analysis of the coefficient of linear-circular dichroism of two-photon absorption of light is carried out. Expressions are obtained for the spectral dependence of the coefficient of interband two-photon absorption of light in narrow-gap semiconductors in the Kane model.

Two-photon absorption of styryl-quinolinium, -pyridinium, and -barbituric acid derivatives, and intramolecular charge transfer

2001 ◽  
Vol 79 (2) ◽  
pp. 174-182 ◽  
Author(s):  
XiaoMei Wang ◽  
Chun Wang ◽  
WenTao Yu ◽  
YuFang Zhou ◽  
Xian Zhao ◽  
...  
Keyword(s):  
Dipole Moment ◽  
Charge Transfer ◽  
Barbituric Acid ◽  
Intramolecular Charge Transfer ◽  
Theoretical Calculations ◽  
Photon Absorption ◽  
Amino Groups ◽  
Element Analysis ◽  
Two Photon Absorption ◽  
Two Photon

A series of new chromophores, styryl-parent end-capped with various donors, and with barbituric acid, methyl-pyridinium, and methyl-quinolinium as the acceptors, have been synthesized and characterized by element analysis or X-ray diffraction. Using the Z-scan system, their two-photon absorption (TPA) cross-section values (δ) have been determined under excitation with 10 Hz, and 1064 nm, 35 ps mode-locked Nd:YAG laser pulse in DMF with do= 0.05 M. The effective δ value is as high as 10.9 × 10–48 cm4 s per photon for trans-4-(4'-N,N-diphenyl amino) styryl-N-methyl quinolinium iodide (DPASQI). The δ value increases from barbituric acid- to pyridinium- to quinolinium-derivatives apparently due to the increase in both the conjugated degree and planarity; however, when the acceptor is fixed, the δ value increases from dialkyl amino groups to diphenyl amino groups even though the latter is a weaker donor than the dialkyl amino groups. Theoretical calculations confirm that the increased distortion from planarity for the barbituric acid derivative makes its δ value decrease. The relatively large δ value for quinolinium- or pyridinium-derivatives originates from larger intramolecular charge transfer, which can be characterized by the difference of dipole moment (Δµge) between the S0 and S1, and the transition dipole moment (Mee') between S1 and S2.Key words: two-photon absorption, intramolecular charge transfer, styryl-quinolinium, styryl-pyridinium, styryl-barbituric acid.

Computational Study of the One- and Two-Photon Absorption and Circular Dichroism of (l)-Tryptophan

2010 ◽  
Vol 114 (19) ◽  
pp. 6500-6512 ◽  
Author(s):  
Maxime Guillaume ◽  
Kenneth Ruud ◽  
Antonio Rizzo ◽  
Susanna Monti ◽  
Zijing Lin ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Computational Study ◽  
Photon Absorption ◽  
Two Photon Absorption ◽  
Two Photon ◽  
The One ◽  
Circular Dichroïsm

scholarly journals Tuning of Hyperpolarizability, One- and Two-Photon Absorption of D-A and D-A-A Type Intramolecular Charge Transfer Based Sensors

2019 ◽  
Author(s):  
Pralok K. Samanta ◽  
Md Mehboob Alam ◽  
Ramprasad Misra ◽  
Swapan K. Pati
Keyword(s):  
Charge Transfer ◽  
Gas Phase ◽  
Density Functional ◽  
Intramolecular Charge Transfer ◽  
Photon Absorption ◽  
First Hyperpolarizability ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Nlo Response ◽  
Donor Acceptor

Solvents play an important role in shaping the intramolecular charge transfer (ICT) properties of π-conjugated molecules, which in turn can affect their one-photon absorption (OPA) and two-photon absorption (TPA) as well as the static (hyper)polarizabilities. Here, we study the effect of solvent and donor-acceptor arrangement on linear and nonlinear optical (NLO) response properties of two novel ICT-based fluorescent sensors, one consisting of hemicyanine and dimethylaniline as electron withdrawing and donating groups (molecule 1), respectively and its boron-dipyrromethene (BODIPY, molecule 2)-fused counterpart (molecule 3). Density functional theoretical (DFT) calculations using long-range corrected CAM-B3LYP and M06-2X functionals, suitable for studying properties of ICT molecules, are employed to calculate the desired properties. The dipole moment (µ) as well as the total first hyperpolarizability (β<sub>total</sub>) of the studied molecules in the gas phase is dominantly dictated by the component in the direction of charge transfer. The ratios of vector component of first hyperpolarizability (β<sub>vec</sub>) to β<sub>total</sub> also reveal unidirectional charge transfer process. The properties of the medium significantly affect the OPA, hyperpolarizability and TPA properties of the studied molecules. Time dependent DFT (TDDFT) calculations suggest interchanging between two lowest excited states of molecule 3 from the gas phase to salvation. The direction of charge polarization and dominant transitions among molecular orbitals involved in the OPA and TPA processes are studied. The results presented are expected to be useful in tuning the NLO response of many ICT-based chromophores, especially those with BODIPY acceptors.<br>

COEFFICIENT OF INTERBAND TWO-PHOTON ABSORPTION OF LIGHT AND ITS LINEAR-CIRCULAR DICHROISM

2021 ◽  
pp. 39-43
Author(s):  
V. R. Rasulov ◽  
R. Y. Rasulov ◽  
B. B. Axmedov ◽  
I. A. Muminov ◽  
M. X. Qo’chqorov
Keyword(s):  
Circular Dichroism ◽  
Photon Absorption ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Absorption Of Light ◽  
Circular Dichroïsm

Some new aspects of lanthanide optical spectroscopy: circular dichroism and two-photon absorption

1990 ◽  
Vol 102 (3) ◽  
pp. 255-268
Author(s):  
Mihir Chowdhury ◽  
A. K. Banerjee ◽  
T. Kundu ◽  
L. Kundu ◽  
T. Chakraborty
Keyword(s):  
Circular Dichroism ◽  
Optical Spectroscopy ◽  
Photon Absorption ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Circular Dichroïsm
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