Photodissociation of partially fluorinated alkyl iodides in their A-band

Kavita, K and Das, PK (2001) Photodissociation of partially fluorinated alkyl iodides in their A-band. In: Journal Of Physical Chemistry A, 105 (2). pp. 315-318.

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Abstract

Photodissociation dynamics of partially substituted alkyl iodides with fluorine atoms at beta and gamma positions has been investigated. The iodine atoms in the ground I(-P-3/2) and spin-orbit excited I*(P-2(1/2)) states produced in the ultraviolet photolysis of CF3CH2I, C6F13CH2CH2I, and C8F17CH2CH2I have been detected using a two photon laser induced fluorescence (TPLIF) scheme. The I*: quantum yield of the above iodides at 222, 236, 266, 280, and similar to 305 nm corresponding to the red and blue wings as well as the peak of their A-band absorption spectrum has been determined. The I* yield from beta and gamma -substituted iodides is found to remain more or less unchanged as a function of excitation wavelength below 262 nm, which is the peak of their A-band. The observed dynamics at 222, 236, and 266 nm can be adequately described by the known Landau-Zener curve crossing model between the (3)Q(0) and (1)Q(1) states. However, at wavelengths above 262 nm, the measured I* quantum yield of beta and gamma-substituted alkyl iodides reflects that the (3)Q(1) state has a significant contribution to the overall dynamics. The electronic effect exerted by fluorine on the dynamics appears to wither as the substitution moves further away from the C-I bond.

Item Type:	Journal Article
Publication:	Journal Of Physical Chemistry A
Publisher:	American Chemical Society
Additional Information:	Copyright of this article belongs to American Chemical Society.
Keywords:	Magnetic Circular-Dichroism;Potential-Energy Surfaces;Flight Mass-Spectrometry;248 Nm; Ultraviolet Photodissociation;Recoil Anisotropy;Quantum Yields;Methyl-Iodide;Photofragmentation Dynamics;Relative Populations
Department/Centre:	Division of Chemical Sciences > Inorganic & Physical Chemistry
Date Deposited:	04 Feb 2010 04:52
Last Modified:	19 Sep 2010 04:56
URI:	http://eprints.iisc.ac.in/id/eprint/17235

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