کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5403387 | 1392758 | 2007 | 12 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Experimental and theoretical studies of electronic energy states of methyl benzoate derivatives
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کلمات کلیدی
THFEtOHCTMMCHIPTEthanol - اتانولIntramolecular charge transfer - انتقال اتمی مولکولیIntramolecular proton transfer - انتقال پروتون بین داخل مولکولیTetrahydrofuran - تتراهیدروفورانAbsorption and emission spectra - طیف جذب و انتشارICT - فناوری اطلاعات و ارتباطات Methyl benzoate - متیل بنزواتMethylcyclohexane - متیل سیکلوهگزینSemiempirical calculation - محاسبه نیمه تجربیhexane - هگزین
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی تئوریک و عملی
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چکیده انگلیسی
Spectroscopic steady state studies of four monosubstituted derivatives of methyl benzoate dissolved in methylcyclohexane (McH), tetrahydrofuran (THF), ethanol (EtOH) and isopentane-diethyl ether mixture (IP-DE) have been performed at 293 and 77Â K. The determined electronic energy values and oscillator strengths are compared with those obtained from quantum chemical calculations. Good agreement between experimental and theoretical energy values is noted. The average ÎEi=|Eiexp-Eith| value is smaller than 5 percent. A reasonable agreement is noted between intensities of separated bands and oscillator strength of corresponding transitions. The relative ratio of fluorescence to phosphorescence intensity Ifl/Iph of ortho-substituted compounds dissolved in non-polar, polar and protic solvents is higher than that of the para-substituted derivatives of methyl benzoate. The spectroscopic studies show that methyl ortho-hydroxy benzoate in the excited state S1 forms H-bonded dimers in the solvents used. At 77Â K the dimer fluorescence dominates the phosphorescence emission. The long wavelength absorption band (C) of amino-substituted methyl benzoates consists of two transitions in agreement with our theoretical calculations and a suggestion made by Shabestary and El-Bayoumi [N. Shabestary, M.A. El-Bayoumi, Chem. Phys. Lett. 106 (1984) 107].
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Luminescence - Volume 126, Issue 2, October 2007, Pages 665-676
Journal: Journal of Luminescence - Volume 126, Issue 2, October 2007, Pages 665-676
نویسندگان
Marek Aleksiejew, Janina R. Heldt,