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Slichter, C.P. Sakaie, Ken Earl 2011-04-20T18:51:56Z 2011-04-20T18:51:56Z 10000-01-01 1996 "This thesis describes NMR measurements involving carbon-13, deuterons, and protons in acetylene (C2H2) adsorbed at room temperature on supported platinum catalysts. Measurements from 77""K to 158°K of the spin-lattice relaxation behavior of carbon-13 reveal multiple-exponential behavior. Calculations rule out an anisotropic T 1 as an explanation for the multiple-exponential behavior. Carbon-proton SEDOR measurements indicate that each time constant, T 1, in the spin-lattice relaxation of carbon corresponds to a mixture of adsorbate structures. The T 1 seems to exhibit a linear temperature dependence, indicating interaction with conduction electrons of the platinum . clusters. However, the spectrum measurements indicate no Knight shift, a deviation from the Korringa relation. Such a deviation implies that electronic states at the Fermi energy involve hybrids of the platinum conduction band with adsorbate molecular orbitals with no spatial density at the carbon nucleus. Measurements of the deuterium spectrum reveal no obvious features that would prove useful in identifying different adsorbate structures. Spectrum and spin-locking measurements indicate no motion of deuteron groups at 77°K The deuterium spin-lattice relaxation rate exhibits multiple-exponential behavior. Measurements of the coupling between the magnetic dipole moments of deuterons determine bond angles and internuclear distances. A single-resonance ""slow beat"" measurement finds, in deuterated ethylidyne (CCD3) , a distance between deuterons ofr00 = 1.673±0.004A. A double resonance method, demonstrated in a test sample ofD20 in gypsum, can provide bond angle and internuclear distance information. Coherence transfer between carbon and deuterium indicates that deuterium NMR measurements at lower temperatures may offer significant advantages in terms of signal to noise ratios." Submitted by Carolyn Mead (cmead2@illinois.edu) on 2011-04-20T18:51:56Z No. of bitstreams: 1 1996_sakaie.pdf: 4222555 bytes, checksum: e13b9f0c6ea35c4cfb35a499db01816c (MD5) Made available in DSpace on 2011-04-20T18:51:56Z (GMT). No. of bitstreams: 1 1996_sakaie.pdf: 4222555 bytes, checksum: e13b9f0c6ea35c4cfb35a499db01816c (MD5) Previous issue date: 1996 Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Carolyn Mead (cmead2@illinois.edu) on 2011-04-20T18:51:56Z Item is restricted indefinitely. Restriction data tranferred 2014-07-01T11:10:04-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: Thesis Thesis U of I Only 4014280 http://hdl.handle.net/2142/18847 en 1996 Ken Earl Sakaie Nuclear magnetic resonance (NMR) acetylene platinum catalysts NMR studies of acetylene absorbed on supported platinum catalysts Dissertation / Thesis text Physics Physics University of Illinois at Urbana-Champaign Dissertation Ph.D.