Direct observation of the vibrational energy redistribution in (CF3)2CCO molecules resonantly excited by femtosecond infrared laser radiation

Компанец, В. О.; Laptev, V. B.; Макаров, А. А.; Pigulsky, S. V.; Ryabov, E. A.; Чекалин, С. В.

doi:10.1134/s0021364010150038

Cited by 9 publications

(3 citation statements)

References 13 publications

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“…[15]). The other applied techniques of probing-infrared absorbtion [18][19][20][21][22] and UV ionization [23][24][25][26]-have not demonstrated such capability yet.…”

Section: Photon Echoes For Studying Intramolecular Vibrational Redist...mentioning

confidence: 99%

Photon echoes for studying intramolecular vibrational redistribution: on determination of the dilution factors

Макаров¹

2014

Laser Phys.

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A theory of the photon echo is presented for excitation of the vibrational-rotational transitions in a polyatomic molecule followed by the process of intramolecular vibrational redistribution (IVR). A model is considered that includes a description of IVR using the general statistical properties of chaotic states rather than phenomenological. Special attention is paid to the echo signals at the delay times that are considerably larger than the characteristic times of IVR. It is shown that echo measurements for the far plateau of the IVR curve can provide, directly or indirectly, determination of the so-called dilution factors; their values are of primary importance for estimating effective density of the molecular states that participate in IVR. Differences between the echo and anti-Stokes Raman scattering, really used for the same purposes, are discussed.

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“…[15]). The other applied techniques of probing-infrared absorbtion [18][19][20][21][22] and UV ionization [23][24][25][26]-have not demonstrated such capability yet.…”

Section: Photon Echoes For Studying Intramolecular Vibrational Redist...mentioning

confidence: 99%

Photon echoes for studying intramolecular vibrational redistribution: on determination of the dilution factors

Макаров¹

2014

Laser Phys.

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“…The next step has been made in our studies , of the vibrational dynamics in different modes of the (CF 3 ) 2 CCO molecule, in which the mode ν 1 = 2194 cm –1 of the asymmetric vibration of the CCO bond was excited by resonant femtosecond IR radiation. It was shown that the selective multiphoton excitation of this mode takes place, which is noticeable up to the level v = 7.…”

Section: Introductionmentioning

confidence: 99%

Intramolecular Vibrational Dynamics in Free Polyatomic Molecules with C═O Chromophore Bond Excited by Resonant Femtosecond IR Laser Radiation

et al. 2014

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In nine polyatomic molecules, we have studied the intramolecular redistribution of vibrational energy from chromophore C═O group excited by a resonant femtosecond IR laser radiation at a wavelength of ∼5 μm. All experiments have been performed in the gas phase using the IR-IR pump-probe technique in combination with the spectral analysis of the probe radiation. For molecules with one C═O end group, characteristic times of intramolecular vibrational redistribution (IVR) lie in the range between 2.4 and 20 ps and correlate with the density of four-frequency Fermi resonances. The IVR times in metal carbonyl molecules are anomalously long, being ∼1.0 ns for Fe(CO)5 and ∼1.5 ns for Cr(CO)6. In the CH3(C═O)OC2H5 and H2CCH(C═O)OC2H5 molecules, it has been observed that there are two characteristic IVR times, which differ by an order of magnitude from each other; this was interpreted in terms of the developed model of "accumulating states". For the ICF2COF molecule, it has been revealed that the IVR time decreases with increasing level of the vibrational excitation of the C═O bond of the molecule.

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“…At that time, it was assumed, in general, that typical IVR times lie in the range from several hundreds of femtoseconds (from spectroscopy of benzene overtones [42,43]) to tens of picoseconds. The most recent example falling into this range is reported in [44,45] where selective excitation of the C C O bond in (CF 3 ) 2 CCO has been observed by pump-probe time-resolved absorption spectroscopy up to an energy of about 10 000 cm −1 within a time scale of several picoseconds. Such studies require femtosecond laser pulses, and their usage in the middle IR is not routine so far.…”

Section: Introductionmentioning

confidence: 99%

Slow intramolecular vibrational redistribution: the latest results for trifluoropropyne, a comparison with the other terminal acetylenes and the mechanism*

2012

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We studied the dynamics of intramolecular vibrational redistribution (IVR) from the initially excited mode ν1≈3330 cm−1 (acetylene-type H–C bond) in molecules in the gaseous phase by means of time-resolved anti-Stokes spontaneous Raman scattering. The time constant of this process was estimated as 2.3 ns—this is the slowest IVR time reported so far for the room-temperature gases. We have compared this result with earlier results on the other terminal acetylene molecules, and give an explanation of this low IVR rate. Our suggestion for it follows from an assumption that the most probable doorway state leading to IVR from to the bath of all vibrational–rotational states consists of one quantum of the stretch and two quanta of the bend, and the matter is that the energy defect of Fermi resonance is essentially larger in trifluoropropyne than in other similar molecules. In addition, we have obtained the rate of collision-induced IVR for trifluoropropyne from experiments with various gas pressures and have shown that the observed dynamics is in agreement with a theoretical model assuming strong vibrational–rotational mixing.

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Direct observation of the vibrational energy redistribution in (CF3)2CCO molecules resonantly excited by femtosecond infrared laser radiation

Cited by 9 publications

References 13 publications

Photon echoes for studying intramolecular vibrational redistribution: on determination of the dilution factors

Photon echoes for studying intramolecular vibrational redistribution: on determination of the dilution factors

Intramolecular Vibrational Dynamics in Free Polyatomic Molecules with C═O Chromophore Bond Excited by Resonant Femtosecond IR Laser Radiation

Slow intramolecular vibrational redistribution: the latest results for trifluoropropyne, a comparison with the other terminal acetylenes and the mechanism*

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