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

详细信息    查看全文

• 作者：Sergey V. Chekalin ; Victor O. Kompanets ; Pavel V. Koshlyakov ; Vladimir B. Laptev ; Sergey V. Pigulsky ; Alexander A. Makarov ; Evgeny A. Ryabov
• 刊名：Journal of Physical Chemistry A
• 出版年：2014
• 出版时间：February 13, 2014
• 年：2014
• 卷：118
• 期：6
• 页码：955-964
• 全文大小：405K
• ISSN：1520-5215

文摘

In nine polyatomic molecules, we have studied the intramolecular redistribution of vibrational energy from chromophore C鈺怬 group excited by a resonant femtosecond IR laser radiation at a wavelength of 5 渭m. All experiments have been performed in the gas phase using the IR鈥揑R pump鈥損robe technique in combination with the spectral analysis of the probe radiation. For molecules with one C鈺怬 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鈺怬)OC₂H₅ and H₂CCH(C鈺怬)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 鈥渁ccumulating states鈥? For the ICF₂COF molecule, it has been revealed that the IVR time decreases with increasing level of the vibrational excitation of the C鈺怬 bond of the molecule.