UScholar Works
 
Filters: Collection: "ir_uspace" Subject: "NMR"
1 - 25 of 28
Number of results to display per page
CreatorTitleDescriptionSubjectDate
1 Ailion, David Charles109Ag NMR investigation of atomic motions in the incommensurate and paraelectric phases of proustite (Ag3AsS3)109Ag NMR line shape, T1 , Hahn spin echo, and Carr-Purcell-Meiboom-Gill ~CPMG! spin-echo measurements were performed in proustite (Ag3AsS3) between 420 and 47 K in order to understand the role of atomic motions in phase transitions in a system containing an incommensurate phase. These measurements ...NMR; Atomic motion; Proustitie; Phase transitions; Line shape2000
2 Ailion, David Charles14N study of the role of N-D---O bonds in the deuteron glass transition14N spin-lattice relaxation-time measurements in Rb0.28(ND4)0.72D2PO4 provide direct evidence for the fast exchange averaging of the "long" and "short" N-D---O hydrogen bonds between the ND4 group and the four surrounding PO4 groups. This exchange and the associated distortion of the ND4 tetrahedron...NMR; Hydrogen bonds; Spin-lattice; Relaxation-time; Deuteron glass1999
3 Ailion, David Charles31P NMR spin-lattice relaxation: structural glass dynamics in Rb1-x(ND4)xD2PO4We performed 3 1P NMR measurements of the temperature-dependent spin-lattice relaxation time in several mixed single crystals of Rbi_x(ND4 ) xD2P04 [DRADP] having different ammonium concentration x (x =0.22, 0.44, 0.78) as well as in three pure single crystals (ND4)D2P04 [DADP], (NH4)H2P04 [ADP], an...NMR; Spin-lattice; Relaxation; Crystals; Glass; Spin-glass1993
4 Ailion, David Charles93Nb NMR in the imcommensurate and quasi-commensurate phases of barium sodium niobateNMR spectra have been measured for the quadrupole perturbed 1/2 -1/2 transition of 9 3Nb in barium sodium niobate (BSN) between 300 and 650 K. The spectra are inhomogeneously broadened in the incommensurate (/) phase between T7 = 580 K and r c = 540 K as well as in the quasicommensurate (QC) phase ...NMR; Spectra; Barium sodium niobate; Line shapes1994
5 Gesteland, Raymond F.; Wills, Norma M.; Atkins, John F.Comparative studies of frameshifting and nonframeshifting RNA pseudoknots: a mutational and NMR investigation of pseudoknots derived from the bacteriophage T2 gene 32 mRNA and the retroviral gag-pro frameshift siteMutational and NMR methods were used to investigate features of sequence, structure, and dynamics that are associated with the ability of a pseudoknot to stimulate a "1 frameshift. In vitro frameshift assays were performed on retroviral gag-pro frameshift-stimulating pseudoknots and their derivati...Frameshifting; NMR; Pseudoknot; Retrovirus2002
6 Ailion, David CharlesDetection of slow modulation wave diffusion in incommensurate barium sodium niobate by 93Nb 2D exchange NMR93Nb two-dimensional (2D) exchange NMR was used to study ultraslow motions in incommensurate barium sodium niobate (BSN) in the temperature range 500 - 560 K. These 2D exchange data provide strong evidence for diffusionlike motion of the modulation wave in BSN. Such motions in BSN had been previousl...NMR; Hahn spin-echo decay; Incommensurate systems.2001
7 Ailion, David CharlesEffect of the translational diffusion mechanism on the low-field NMR spin-lattice relaxation time in the rotating reference frame: calculation of order parameterThe effect of the translational-diffusion mechanism on the low-field NMR spin-lattice relaxation time in the rotating reference frame is calculated for simple cubic, body-centered cubic, and face-centered cubic lattices. The results of these calculations suggest a new method for determining the pref...NMR; Nuclear magnetic resonance; Lattices; Relaxation time1968
8 Ailion, David CharlesEvidence for elastic disorder in the elastically ordered phase of KCNWe have obtained evidence from 1 3C NMR measurements that the CN~ ion in the elastically ordered phase of KCN is misoriented slightly with respect to the orthorhombic b axis. This misorientation varies randomly over the lattice, averaging to zero on a macroscopic scale. The misorientations are mani...Potassium cyanide; Anisotropy; Orthorhombic crystal; NMR; Nuclear magnetic resonance1981
9 Ailion, David CharlesFrequency modulation method for performing adiabatic demagnetization in the rotating reference frameA new method for preforming adiabatic demagnetization in the rotating reference frame in NMR experiments is presented in this paper. In this new method the frequency of a crystal oscillator rather than the actual magnetic field is pulsed off resonance. Using simple circuits which are described in th...Demagnetization; Physics experiments; NMR1970
10 Ailion, David CharlesGallium and thallium NMR study of phase transitions and incomemensurability in the layered semiconductor TlGaSe2We report on the first NMR study of phase transitions and incommensurability in the layered semiconductor TlGaSe2. 69,71Ga and 205Tl NMR data from a powder sample show phase transitions at 118, 108 and around 69 K. The 69Ga and 71Ga spin-lattice relaxation times T1 are short and nearly temperature i...NMR; Atomic motion; Phase transitions; Spin-lattice; Relaxation-time2004
11 Ailion, David CharlesHigh sensitivity nuclear quadrupole resonance approach for detection of modulation wave motion in incommensurate systemsIn contrast to conventional NMR techniques that use magnetic field gradients (MFCs) to detect the diffusion of moving atoms, we have developed a highly sensitive approach for detecting electric field gradient (EFG) fluctuations seen by stationary atoms. These EFG fluctuations were observed in the ...NMR; MFG; Magnetic field gradients; Diffusion constants; Atoms; Nuclei1995
12 Saam, Brian; Laicher, GernotLiquid hyperpolarized 129Xe produced by phase exchange in a convection cellWe present a method for the production of liquid hyperpolarized 129Xe that employs spin-exchange optical pumping in the gas phase and subsequent phase exchange with a column of xenon liquid. A convection loop inside the sealed glass cell allows efficient transfer of magnetization between the gas an...Liquid hyperpolarized 129Xe; Phase exchange; Spin-exchange optical pumping; SEOP; NMR; Spin polarization2004
13 Ailion, David CharlesNature of Ag+ self-diffusion in AgFMeasurements of the nuclear magnetic resonance (NMR) dipolar relaxation times T w and T i (51°) have been made on the 1 9 F resonance in AgF powder over the temperature range 60-300 K. Also the technique of Stokes and Ailion for detecting the diffusion of weakly magnetic spins has been verified f...NMR; Nuclear magnetic resonance; Diffusion; Ionic conductivity1981
14 Ailion, David CharlesNature of the incommensurate-paraelectric transition: a two dimensional exchange-difference NMR study87Rb two-dimensional exchange-difference NMR was used to study collective motions in the incommensurate (I) and paraelectric (P) phases of Rb2ZnCl4, which elucidate the nature of the I-P transition. We measured the cross-peak frequency displacement vs mixing time and observed a gradual increase towa...Incommensurate systems; NMR; Paraelectric phase2000
15 Ailion, David CharlesNew NMR techniques to study diffusion in multispin crystalsWe present a new NMR method for studying slow diffusion in multispin systems. With this method we can vary the effect of a particular spin species' motion relative to the others, thus enabling us to separate and identify the component motions. We present a new pulse sequence for measuring T1L', a ge...NMR; Nuclear magnetic resonance; Crystals; Nuclear-spin species; Diffusion; Molecular rotations1977
16 Ailion, David CharlesNew technique for determining the diffusion mechanism by NMR: application to Cl35 diffusion in TlClA major problem in the study of atomic motions is the determination of the dominant mechanism responsible for translational diffusion. Recently Ailion and Ho predicted that the rotating-frame spin-lattice relaxation time T l p would have an angular dependence which depends on the diffusion mechanis...Diffusion; Solids; NMR1972
17 Ailion, David CharlesNMR determination of structural domains in NaCNMeasurements of the first- and second-order quadrupole energy-level shifts are performed in a 23Na NMR experiment in a single crystal of NaCN. Twelve orthorhombic domains are found below the phase transition at 15°C. They consist of six pairs of domains with each one oriented by an angle 2/3 rel...NMR; Nuclear magnetic resonance; Crystals; Structural domains1980
18 Ailion, David CharlesNMR determination of the Edwards-Anderson order parameter in the deuterated pseudo-spin glass Rb1-x(ND4)xD2PO4: anisotropy and concentration dependence of the ND4 deuteron second momentWe measured the rotationally averaged N D 4 + deuteron second moment in deuterated mixed single crystals Rb1_x(ND4 ) xD2P04 with x = 0.22, 0.44, 0.78, and pure ND4D2P04 . We found that the linewidths of the mixed systems show a strong dependence on the crystal's orientation with respect to the exter...NMR; Crystals; Deuteron second moment; Anisotropy; Linewidth1990
19 Ailion, David CharlesNMR in lithium metal: thermal mixingWe present a calculation of the thermal mixing rate t~ 1 between nuclear Zeeman and dipolar reservoirs in the presence of large rf fields. We applied this calculation to slow-motion diffusion in lithium metal. In particular, we measured the rotating frame spin-lattice relaxation time Tl p as a funct...NMR; Nuclear magnetic resonance; Lattices; Relaxation time1977
20 Ailion, David CharlesNMR in substitutionally disordered incommensurate (Rb1-xKx)2ZnCl4The impurity-concentration dependence of the 8 7Rb NMR line shapes and phason-induced spin-lattice relaxation rates has been studied over a wide temperature range in substitutional^ disordered incommensurate (Rb1_xKJ C)2ZnCl4 for x =0.00, 0.02, and 0.06. The results yield information on the impurity...NMR; Line shapes; Phasons; Spin-lattice; Phase fluctuations1994
21 Ailion, David CharlesNMR lineshapes and order parameter determination in proton pseudo-spin glassesThe quadrupole-perturbed NMR line shape has been evaluated in the local approximation for an arbitrary static random-field distribution coexisting with Gaussian time-fluctuating random fields. The special case of a spin-glass-type static local random-field distribution is treated also. The results ...NMR; Nuclear magnetic resonance; Line shape; Random fields; Proton pseudo-spin-glasses1988
22 Ailion, David CharlesNMR methods for identifying and studying diffusion of different spin species in heteronuclear systemsWe introduce a new dipolar relaxation lime TU)' which characterizes the spin-lattice relaxation of secular dipolar interactions in the presence of a large rf field. Measurements of T]D' are particularly useful for studying slow atomic motions in muitispin systems, since such measurements enable us ...NMR; Nuclear magnetic resonance; Nuclear-spin species; Diffusion; Molecular rotations1978
23 Ailion, David CharlesNMR observations of molecular motions and Zeeman-quadrupole cross relaxation in 1,2- difluorotetrachloroethaneWe report measurements of "F NMR relaxation times Tu Tlf, TID, and T2 in the plastic crystal CFCL2-CFCL2 . From the data near the melting point, we obtain the jump time for translational selfdiffusion. At lower temperatures, we observe on the cold side of the T, and Tif minima an unusual field depe...NMR; Nuclear magnetic resonance; Order-disorder; Diffusion1979
24 Ailion, David CharlesNMR relaxation study of molecular motions between unequal potential wells in solid trans, trans- muconodinitrileWe report observations of extremely unusual proton NMR relaxation rates in solid trans, transmuconodinitrile (TMD, N=C-CH = CH-CH = CH-C = N). In particular we measured, over the temperature range 77-423 °K, proton dipolar relaxation times Tw and spin lattice relaxation times Tt (at 24 and 58 MH...NMR; Nuclear magnetic resonance; Lattices; Relaxation time1977
25 Ailion, David CharlesNuclear magnetic resonance in LiF: a single nuclear-dipolar-spin temperature in crystals with more than one spin speciesIn a crystal containing more than one species of nuclear spin in a large dc magnetic field, the secular dipolar interactions between all spins, unlike as well as like, form a single reservoir described by a single spin temperature. We demonstrated this concept with experiments on LiF. In particula...Spin species; Spin-lattice relaxation; NMR; Nuclear magnetic resonance1977
1 - 25 of 28