A study on the electronic spectra of some 2-azidobenzothiazoles, TD–DFT treatment

Abu‐Eittah, Rafie H.; El‐Taher, S.; Hassan, Walid M.I.; Noamaan, Mahmoud A.

doi:10.1016/j.saa.2015.06.119

Cited by 1 publication

(2 citation statements)

References 22 publications

(16 reference statements)

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“…The lowest emission wavelength was found for o -xylene at 267 nm, in comparison with m -xylene at 269 nm and p -xylene at 307 nm. The theoretical wavelengths of absorption spectra and emission spectra were also assigned in π–π* characterization from the HOMO to the LUMO [ 47 , 48 ] ( figure 7 ). The Stokes shift for p -xylene was about 17 nm, whereas that for o - and m -xylene was 18 and 16 nm, respectively.…”

Section: Resultsmentioning

confidence: 99%

“…The lowest emission wavelength was found for o-xylene at 267 nm, in comparison with m-xylene at 269 nm and p-xylene at 307 nm. The theoretical wavelengths of absorption spectra and emission spectra were also assigned in π-π * characterization from the HOMO to the LUMO [47,48] (figure 7 was also considered by using the CPCM. The theoretical emission wavelengths of the three isomers exhibit similar trends with regard to absorption spectra.…”

Section: Emissionmentioning

confidence: 99%

See 1 more Smart Citation

Fluorescence and photophysical properties of xylene isomers in water: with experimental and theoretical approaches

Khan¹,

Wu²,

Liu³

et al. 2018

R. Soc. open sci.

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A thorough analysis of the photophysical properties involved in electronic transitions in excitation–emission spectra of xylene isomers has been carried out using the time-dependent density functional theory (PBEPBE/6-31 + G(d,p)) method. For the first time a structural and spectroscopic investigation to distinguish isomers of xylene, a widespread priority pollutant, was conducted experimentally and theoretically. The fluorescence properties of xylene isomers (sole and mixture (binary and ternary)) in water were studied. The fluorescence peak intensities of xylenes were linearly correlated to concentration, in the order of p-xylene > o-xylene > m-xylene at an excitation/emission wavelength (ex/em) of 260 nm/285 nm for o-, m-xylene and ex/em 265 nm/290 nm for p-xylene at the same concentration. The theoretical excitation/emission wavelengths were at ex/em 247 nm/267 nm, 248 nm/269 nm and 251 nm/307 nm for o-, m- and p-xylene, respectively. The vertical excitation and emission state energies of p-xylene (ex/em 4.94 eV/4.03 eV) were lower and the internal conversion energy difference (0.90 eV) was higher than those of m-xylene (ex/em 5.00 eV/4.60 eV) (0.4 eV) and o-xylene (ex/em 5.02 eV/4.64 eV) (0.377 eV). The order of theoretical emission and oscillator strength (0.0187 > 0.0175 > 0.0339) for p-xylene > o-xylene > m-xylene was observed to be in agreement with the experimental fluorescence intensities. These findings provide a novel fast method to distinguish isomers based on their photophysical properties.

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Section: Resultsmentioning

confidence: 99%

“…The lowest emission wavelength was found for o-xylene at 267 nm, in comparison with m-xylene at 269 nm and p-xylene at 307 nm. The theoretical wavelengths of absorption spectra and emission spectra were also assigned in π-π * characterization from the HOMO to the LUMO [47,48] (figure 7 was also considered by using the CPCM. The theoretical emission wavelengths of the three isomers exhibit similar trends with regard to absorption spectra.…”

Section: Emissionmentioning

confidence: 99%