Radiationless Deactivation of Singlet Excited States of Complex Molecules in the Gas Phase

Borisevich, N. A.; Bolot'ko, L. M.; Raichyonok, T. F.

doi:10.1080/00387018208062653

Cited by 22 publications

(13 citation statements)

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“…When λ ex decreases, the fluorescence spectrum is slightly shifted toward lower frequencies, its halfwidth increases, and the vibrational structure is washed out. Such a behavior of the fluorescence spectra is typical of rarefied vapor of complex molecular compounds [9]. Consequently, for a vapor temperature of T 1 = 102 o C and a temperature T 2 = 68 o C (setting the vapor pressure), the indole molecules in the excited electronic state do not interact with each other.…”

Section: Introductionmentioning

confidence: 98%

“…In order to check the purity of the studied indole sample, we obtained the fluorescence excitation spectrum of its solution in hexane, which within the measurement accuracy limits matched the absorption spectrum. The fluorescence quantum yield for free polyatomic molecules in most cases [9] depends on λ ex , and the fluorescence excitation spectra should differ from the absorption spectra. The fluorescence excitation spectra illustrated in Fig.…”

Section: Introductionmentioning

confidence: 99%

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Absorption, fluorescence, and fluorescence excitation spectra of free molecules of indole and its derivatives

Borisevich

Райченок

2007

J Appl Spectrosc

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We have obtained and analyzed the absorption, fluorescence, and fluorescence excitation spectra of indole vapor, N-acetyl-L-tryptophan vapor, and 3-indole aldehyde vapor. From analysis of the dependence of the fluorescence spectrum of the free indole molecules on the wavelength of the exciting radiation λ ex , it follows that emission of fluorescence occurs when the molecules undergo a transition from the one electronically excited state 1 L b . The fluorescence spectra of the studied compounds are insignificantly different, suggesting a major role for the indole chromophore in formation of the compounds. The absorption spectrum of N-acetyl-L-tryptophan, in which the group of atoms is added to the indole ring through a -C-C bond, is similar to the spectrum of indole, while the spectrum of 3-indole aldehyde is significantly different from the indole spectrum due to the effect of the C=O group conjugated with the indole ring. The fluorescence excitation spectra are considerably different from the absorption spectra. This is associated with the strong dependence of the quantum yield for the free molecules on λ ex . Qualitatively, they are mirror-symmetric to the fluorescence spectra of the stodied compounds. Analysis of the data obtained provides a basis for assuming that in the case of free molecules of indole and its derivatives, the 1 L a absorption in the extreme long-wavelength region of the spectrum does not overlap 1 L b absorption.Introduction. Indole is a chromophore in the amino acid series including tryptophan, the luminescence of which is used when studying complex biological systems. It is well known that the medium has a strong effect on the photophysical properties of indole. Accordingly, broad studies have been conducted on different solutions of indole and its derivatives. The results obtained are covered in monographs [1-3] and many other publications, including theoretical papers [4,5]. It is important to study these molecules in the gas phase (where they do not interact with a medium but rather are free molecules), especially rarefied vapor, where they do not interact with each other during the lifetime of the molecules in the excited electronic state. However, there have only been isolated studies of indole and its derivatives in the gas phase.The first data on the absorption spectrum of indole vapor are found in [6], where the authors associate the longest wavelength band in the spectrum with the electronic transition 1 L b , and the maximum of this band at λ max = 283.7 nm is assumed to correspond to a purely electronic transition. A group of weak bands is also assigned to the same electronic transition. The absorption band with maximum wavelength λ max = 274.1 nm, like the subsequent bands at λ max = 260 and 255 nm, is assigned to the second electronic transition 1 L a . This absorption spectrum of indole vapor is given in the monographs [1,2]. In [6], the absorption spectrum of 3-methylindole vapor is obtained, while [7] gives the spectrum of 5-methoxyindole. A problem with these papers was ...

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Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Absorption, fluorescence, and fluorescence excitation spectra of free molecules of indole and its derivatives

Borisevich

Райченок

2007

J Appl Spectrosc

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“…Для сложных молекул возможны два пути безызлучательной дегра-дации энергии электронного возбуждения: безызлучательный переход синглетно-возбужденных молекул в триплетное состояние (интеркомби-национная конверсия), прямой безызлучательный переход молекул из син-глетно-возбужденного состояния в основное (внутренняя конверсия). Недавно удалось выяснить роль этих каналов в безызлучательной дегра-дации поглощенной энергии в свободных сложных молекулах 36 " 39 . Для большинства молекул имеет место как интеркомбинационпая, так и внут-ренняя конверсия.…”

Section: спектрально-люминесцентные характеристики свободных сложных unclassified

Laser action in complex molecules in the gas phase

Borisevich¹,

Tolkachev²

1982

Usp. Fiz. Nauk

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“…We know that the population of electronic and vibrational levels of the molecule under equilibrium conditions follows a Boltzmann distribution: n i /n j = g i /g j exp (-(E i -E j )/kT). The population of the excited electronic level closest to the ground state is insignificant up to temperatures of ≈3000 o C [2]. The population of the first and subsequent vibrational levels changes much faster as the temperature rises, which leads to redistribution of the intensity in the bands of the molecular spectrum.…”

Section: Introductionmentioning

confidence: 97%

Taking into account nonselective absorption of light in atomic absorption analysis

2006

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We propose a method for quantitatively taking into account nonselective absorption for systems in which the vapor phase contains a single molecular form: sodium and potassium chlorides and iodides. We identified the absorption bands using modern quantum chemistry methods. We have demonstrated good agreement between the experimental data and the calculations. We have tested the correctness of the method we developed for the example of determining known silicon and iron contents in potassium chloride and sodium iodide. Differences between the results obtained and the true elemental contents were random.Key words: atomic absorption spectrometry with a graphite furnace, nonselective absorption of light, vapor phase, molecular spectra, sodium and potassium iodides and chlorides.

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Radiationless Deactivation of Singlet Excited States of Complex Molecules in the Gas Phase

Cited by 22 publications

References 2 publications

Absorption, fluorescence, and fluorescence excitation spectra of free molecules of indole and its derivatives

Absorption, fluorescence, and fluorescence excitation spectra of free molecules of indole and its derivatives

Laser action in complex molecules in the gas phase

Taking into account nonselective absorption of light in atomic absorption analysis

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