International Journal of Optics and Photonics
IJOP
Basic Sciences
http://ijop.ir
1
admin
1735-8590
2538-4007
10.52547/ijop
1735-8590
en
jalali
1396
10
1
gregorian
2018
1
1
12
1
online
1
fulltext
en
Absorption of DCM Dye in Ethanol: Experimental and Time Dependent Density Functional Study
عمومى
General
كاربردي
Applicable
<p style="text-align: justify;">Experimental and theoretical absorption spectra of [2-[2-[4-(dimethylamino) phenyl]ethenyl]-6-methyl-4H- pyran-4-ylidene]-propanedinitrile (DCM) have been studied. UV-Visible (UV-Vis.) absorption spectrum of DCM has been reported after its synthesis. Two relatively intense peaks appeared at 473 and 362 nm respectively. A theoretical investigation on the electronic structure of DCM is presented in an effort to rationalize our experimental results. Theoretical results have been obtained with a polarizable continuum model time-dependent density functional theory (PCM-TD-DFT) approach. At first, a vast functional benchmark has been performed to determine a suitable approach for determination of electronic structure and UV-Vis. absorption spectrum of DCM. In a second step, we evaluated the impact of the atomic basis set on the electronic transition energies using a large panel of Pople’s basis sets ,up to the 6-31+G(3df,2p) and also a correlation consistent basis set, cc-pVTZ. It turns out that the selected basis set has a relatively finite influence on the calculated electronic transition energies as well as the topology of the absorption shape, but both are significantly affected by the chosen functional. In the present case, no single functional simultaneously provides highly accurate positions and intensities of the different bands, but mPW1PBE and mPW1LYP appear to be a good compromise. The mPW1PBE along with medium basis sets produced both absorption bands with maximum peaks about 463 and 346 nm. At all stages, ethanol has been chosen as a solvent environment. To improve the accuracy of first electronic excitation, a complete analysis of the origin of the band shape using TD-DFT vibrational couplings was performed. Finally the computed transition energy was corrected to 472 nm which was in excellent agreement with experiments.</p>
TD-DFT, DCM dye, Absorption spectra, Vibrational coupling.
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http://ijop.ir/browse.php?a_code=A-10-449-1&slc_lang=en&sid=1
Seyed Hassan
Nabavi
nabavi@modares.ac.ir
10031947532846002115
10031947532846002115
Yes
Tarbiat Modares University
Mohammad Hassan
Khodabandeh
10031947532846002116
10031947532846002116
No
University of Shahid Beheshti
Maryam
Golbabaee
10031947532846002117
10031947532846002117
No
University of Shahid Beheshti
Ahmad
Moshaii
10031947532846002118
10031947532846002118
No
Tarbiat Modares University