Peter F. McGarry
Columbia University
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Featured researches published by Peter F. McGarry.
Journal of Photochemistry and Photobiology A-chemistry | 1994
Peter F. McGarry; Charles E. Doubleday; Chung-Hsi Wu; Heinz A. Staab; Nicholas J. Turro
Abstract The effect of the molecular geometry of diaryl and arylalky ketones on the rate of intersystem crossing (ISC) was investigated by employing picosecond pump—probe studies of the growth of triplet—triplet absorptions at 532 and 355 nm. Vibrational relaxation within the triplet manifold was found to interfere with measurement of the ISC rates for certain benzophenone derivatives. The observed rapid decay of absorption at 355 nm is attributed to relaxation of vibrationally excited triplets. The trends observed are consistent with direct singlet-to-triplet ISC from S 2 to T 1 .
Journal of Photochemistry and Photobiology A-chemistry | 2002
Peter F. McGarry; Cyril Heitner; John A. Schmidt; Andrew Rodenhiser; R. St. John Manley; Glen Thomas Cunkle; Thomas Friend Thompson
Abstract UV screens used to photostabilise high-yield pulp do not work as well when deposited from water as they do when deposited from organic solvents. For a water-soluble ultraviolet absorber (UVA) based on 2-hydroxybenzophenone, the water-effect is dramatic. For example, during light exposure a 78% ISO brightness paper sheet made from lignin-containing peroxide bleached softwood thermomechanical pulp (BTMP) lost 27 brightness points. A BTMP sheet treated with 0.5% by weight of the UVA 5-benzoyl-4-hydroxy-2-methoxy-benzenesulfonic acid, 1 (Uvinul MS40™) delivered from ethanol lost only 19 brightness points. However, a sheet treated with 0.5% of the same UVA from water lost 25 brightness points. For a benzotriazole UVA, 5-benzotriazolyl-4-hydroxy-3- sec -butyl-benzenesulfonic acid, 2 (Cibafast W™) the adverse water-effect is smaller. Our experiments suggest several reasons for the poor performance of aqueous-delivered 1 : attenuation and broadening of the absorption spectra on paper when the additive is delivered from water, disruption of the internal hydrogen bond, partial formation of phenolate ion, and changes in the distribution of the additive through the thickness of the paper sheet. This effect has been found to be general across several water-soluble benzophenone- and benzotriazole-type UVAs. One exception to the rule is found for a benzotriazole that has a PEO side chain on the hydroxyphenyl ring. Thus, choice of solvent used in testing new paper stabilisers is of central importance to stabiliser performance.
Journal of the American Chemical Society | 1997
Steffen Jockusch; Igor V. Koptyug; Peter F. McGarry; Gregory W. Sluggett; Nicholas J. Turro; Diana M. Watkins
Journal of the American Chemical Society | 1996
Gregory W. Sluggett; Peter F. McGarry; Igor V. Koptyug; Nicholas J. Turro
Archive | 1999
Raymond Seltzer; David Devore; Glen Thomas Cunkle; Cyril Heitner; John A. Schmidt; Peter F. McGarry; Jean-Pierre Wolf; Randall B. Nelson
Journal of Physical Chemistry A | 1997
Peter F. McGarry; Steffen Jockusch; Yoshihisa Fujiwara; Nikolas A. Kaprinidis; Nicholas J. Turro
Journal of the American Chemical Society | 1994
Katsuya Ishiguro; Igor V. Khudyakov; Peter F. McGarry; Nicholas J. Turro; Heinz D. Roth
The Journal of Physical Chemistry | 1993
Igor V. Khudyakov; Peter F. McGarry; Nicholas J. Turro
Tappi Journal | 2006
Zhirun Yuan; Cyril Heitner; Peter F. McGarry
The Journal of Physical Chemistry | 1996
Peter F. McGarry; James L. Cheh; Beatriz Ruiz-Silva; Shuanghua Hu; Jun Wang; Koji Nakanishi; Nicholas J. Turro