Polar modes in molecular crystals: Ewald splitting of infrared and Raman lines

1984 ◽  
Vol 62 (12) ◽  
pp. 1237-1247 ◽  
Author(s):  
Raffaele Guido Della Valle ◽  
Pier Francesco Fracassi
Keyword(s):  
Lattice Dynamics ◽  
Dipole Moments ◽  
Molecular Crystals ◽  
Radiation Polarization ◽  
Transition Dipole ◽  
Line Shapes ◽  
Long Wave ◽  
Transition Dipole Moments ◽  
Powder Samples ◽  
Analytical Expressions

Ewald's long-wave method is applied to long-range electrostatic potentials within the framework of quasi-harmonic lattice dynamics of molecular crystals. The angular dependence of phonon frequencies, transition dipole moments, and polarizabilities of single crystals is derived for all crystallographic species. Analytical expressions for infrared and Raman line shapes in powder samples arc obtained, pointing out the dependence of line shapes on the crystal symmetry and the radiation polarization. The infrared and Raman spectra of polycrystalline HCl are discussed.

scholarly journals Highly effective organic light-emitting diodes containing thermally activated delayed fluorescence emitters with horizontal molecular orientation

RSC Advances ◽  
2020 ◽  
Vol 10 (70) ◽  
pp. 42897-42902
Author(s):  
Chan Hee Lee ◽  
Shin Hyung Choi ◽  
Sung Joon Oh ◽  
Jun Hyeon Lee ◽  
Jae Won Shim ◽  
...  
Keyword(s):  
Dipole Moments ◽  
Delayed Fluorescence ◽  
Organic Light Emitting Diodes ◽  
Host Matrix ◽  
Transition Dipole ◽  
Thermally Activated Delayed Fluorescence ◽  
Light Emitting ◽  
Thermally Activated ◽  
Organic Light ◽  
Transition Dipole Moments

The linear D–A–D type of molecular structure of AcPYM and PxPYM enhances the horizontally oriented alignment and up to 87% of the horizontal transition dipole moments in the host matrix is realized.

scholarly journals Directionality of light absorption and emission in representative fluorescent proteins

2020 ◽  
Vol 117 (51) ◽  
pp. 32395-32401
Author(s):  
Jitka Myšková ◽  
Olga Rybakova ◽  
Jiří Brynda ◽  
Petro Khoroshyy ◽  
Alexey Bondar ◽  
...  
Keyword(s):  
Light Wave ◽  
Fluorescent Proteins ◽  
Dipole Moments ◽  
Biological Processes ◽  
Transition Dipole ◽  
X Ray ◽  
Emission Transition ◽  
Transition Dipole Moments ◽  
Fluorescent Molecules ◽  
Incoming Light

Fluorescent molecules are like antennas: The rate at which they absorb light depends on their orientation with respect to the incoming light wave, and the apparent intensity of their emission depends on their orientation with respect to the observer. However, the directions along which the most important fluorescent molecules in biology, fluorescent proteins (FPs), absorb and emit light are generally not known. Our optical and X-ray investigations of FP crystals have now allowed us to determine the molecular orientations of the excitation and emission transition dipole moments in the FPs mTurquoise2, eGFP, and mCherry, and the photoconvertible FP mEos4b. Our results will allow using FP directionality in studies of molecular and biological processes, but also in development of novel bioengineering and bioelectronics applications.

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