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Affiliation(s)
- Daniel P. Jackson
- a Department of Chemistry and Biochemistry , University of Oklahoma , Norman , OK , 73019-0370 , U.S.A
| | - B. M. Fung
- a Department of Chemistry and Biochemistry , University of Oklahoma , Norman , OK , 73019-0370 , U.S.A
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Lim KC, Margerum JD, Lackner AM, Sherman E, Ho MS, Fung BM, Genetti WB, Grady BP. A Liquid Crystal Based Polymer for Applications in MMW Modulation Devices. ACTA ACUST UNITED AC 2006. [DOI: 10.1080/10587259708041828] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- K. C. Lim
- a Hughes Research Laboratories , Malibu , CA , 90265
| | | | - A. M. Lackner
- a Hughes Research Laboratories , Malibu , CA , 90265
| | - E. Sherman
- a Hughes Research Laboratories , Malibu , CA , 90265
| | - M.-S. Ho
- b Department of Chemistry , University of Oklahoma , Norman , OK , 73019
| | - B. M. Fung
- b Department of Chemistry , University of Oklahoma , Norman , OK , 73019
| | - W. B. Genetti
- c School of Chemical Engineering and Material Science University of Oklahoma , Norman , OK , 73019
| | - B. P. Grady
- c School of Chemical Engineering and Material Science University of Oklahoma , Norman , OK , 73019
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Affiliation(s)
- Shin-Tson Wu
- a Hughes Research Laboratories 3011 Malibu Canyon Road , Malibu , CA , 90265 , USA
| | - J. D. Margerum
- a Hughes Research Laboratories 3011 Malibu Canyon Road , Malibu , CA , 90265 , USA
| | - M. S. Ho
- b Department of Chemistry , The University of Oklahoma Noman , Oklahoma , 73019 , USA
| | - B. M. Fung
- b Department of Chemistry , The University of Oklahoma Noman , Oklahoma , 73019 , USA
| | - C. S. Hsu
- c Department of Applied Chemistry National Chiao Tung University Hsinchu , Taiwan , ROC
| | - S. M. Chen
- c Department of Applied Chemistry National Chiao Tung University Hsinchu , Taiwan , ROC
| | - K. T. Tsai
- c Department of Applied Chemistry National Chiao Tung University Hsinchu , Taiwan , ROC
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Affiliation(s)
- C. W. Cross
- a Department of Chemistry , University of Oklahoma Norman , Oklahoma , 73019-3070 , U.S.A
| | - B. M. Fung
- a Department of Chemistry , University of Oklahoma Norman , Oklahoma , 73019-3070 , U.S.A
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Fung BM, Ermakov VL. The presence of long-lived spin states in organic solids with rapid molecular motions. J Magn Reson 2004; 169:351-359. [PMID: 15261633 DOI: 10.1016/j.jmr.2004.04.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2003] [Revised: 01/21/2004] [Indexed: 05/24/2023]
Abstract
For organic solids with sufficiently mobile molecular segments, the application of a long and weak pulse (gammaB1/2pi approximately Hz) can yield inverted sharp peaks with linewidths of approximately 100 Hz in the 1H NMR spectra, and the use of multi-frequency weak pulses can excite multiple inverted sharp peaks. For these compounds, the normal 1H free induction decay (FID) of a static sample contains a slowly decaying part, which can be detected by acquisition delay up to about 2 ms. The presence of highly mobile molecular segments can also be identified by using a "dipolar filter."
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Affiliation(s)
- B M Fung
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK 73019-3051, USA.
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Affiliation(s)
- B M Fung
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73019-3051, USA.
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Abstract
We have found that the application of a weak radio frequency (rf) pulse to a spin system with indirect spin-spin (J) couplings can produce a narrow inverted peak in spectral regions where there are many overlapping peaks. Examples of three compounds with (1)H-(1)H J couplings and one with (1)H-(13)C J couplings are given. The dependences of the signals on the frequency, duration, and amplitude of the weak rf irradiation have been studied. For an rf power of gammaB(1)/2pi=1.0 Hz, pulse widths longer than 0.25 s consistently produce inverted narrow peaks in spectral regions with unresolved peaks. An interpretation of the origin of this unusual result of selective excitation in spin systems with homogeneous broadening is given: the inverted signal observed can be considered as a cumulative effect of the weak rf irradiation acting on many uncorrelated transitions that are slightly off resonance on both sides of the irradiating frequency; the only role of the J couplings (or dipolar couplings in liquid crystals) is to produce a large number of closely spaced peaks that overlap with each other. Computer simulations of both coupled and noninteracting spin systems have been carried out, and the results support this interpretation.
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Affiliation(s)
- B M Fung
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73019-3051, USA.
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Abstract
The application of a multi-frequency weak pulse to a liquid crystal can excite narrow 1H NMR peaks at the applied frequencies. By using two-level amplitude coding, namely setting the amplitudes of some of the harmonics to zero, this method can be used to store up to 1024 bits of binary information in the liquid crystal molecules. When the information is retrieved in the form of a spectrum, which is plotted as an array of 32 or 16 segments, the stack of spectral segments reproduces a 2D input pattern quite well. This technique is called "NMR photography." The original method was a pseudo-2D technique that applies the 1024-frequency pulse in the first step, and reads the signal row-by-row in the second step. The present improvement involves subtracting two spectra obtained with the same 1024-frequency pulse but with different durations, so that the method becomes a 1D technique, with a tremendous saving of experimental time. Several examples are given to illustrate the results.
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Affiliation(s)
- B M Fung
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK 73019-3051, USA.
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Fung BM, Ermakov VL. A simple method for the preparation of pseudopure states in nuclear magnetic resonance quantum information processing. J Chem Phys 2004; 121:8410-4. [PMID: 15511162 DOI: 10.1063/1.1792594] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The use of nuclear magnetic resonance (NMR) to carry out quantum information processing (QIP) often requires the preparation, transformation, and detection of pseudopure states. In our previous work, it was shown that the use of pairs of pseudopure states (POPS) as a basis for QIP is very convenient because of the simplicity in experimental execution. It is now further demonstrated that the product of the NMR spectra corresponding to two sets of POPS that share a common pseudopure state has the same peak frequencies as those of the common (single) pseudopure state. Examples of applying two different quantum logic gates to a 5-qubit system are given.
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Affiliation(s)
- B M Fung
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK 73019-3051, USA
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Ermakov VL, Fung BM. Nuclear magnetic resonance implementation of the Deutsch–Jozsa algorithm using different initial states. J Chem Phys 2003. [DOI: 10.1063/1.1574802] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Affiliation(s)
- Chibing Tan
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma, 73019-3051
| | - B. M. Fung
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma, 73019-3051
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Affiliation(s)
- Chibing Tan
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73019-3051
| | - B. M. Fung
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73019-3051
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Abstract
Recently it has been shown that the dynamics of a cluster of dipolar-coupled spins can be manipulated to store and process a large amount of information in a parallel way [Chem. Phys. Lett. 360, 161 (2002)]]. Here it is further demonstrated that it is possible to realize a cascade of parallel bitwise operations on a spin cluster so that an algorithm of parallel search can be experimentally implemented by means of nuclear magnetic resonance.
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Affiliation(s)
- Anatoly K Khitrin
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK 73019-3051, USA
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Abstract
We have recently reported phospholipid bicelles (bilayered micelles) that have positive anisotropy of the magnetic susceptibility and align with their normals parallel to an external magnetic field [J. Am. Chem. Soc. 2001, 123, 1537]. Improvements have been made via the synthesis of a new phospholipid, 1-dodecanoyl-2-(4-(4-biphenyl)butanoyl)-sn-glycero-3-phosphocholine (DBBPC). Bicelles can be formed by mixing DBBPC with a short-chain phospholipid, 1,2-dihexanoyl-sn-glycero-3-phosphocholine (DHPC) in a ratio between 5.1:1 and 6.5:1 in an aqueous medium. The (31)P NMR spectra clearly show that these bicelles align with their principal axes parallel to the magnetic field within a wide temperature range. The (31)P chemical shifts indicate that the conformation of the polar headgroup in these bicelles may be different from that in common bicelles. The phase behavior of a mixture of DBBPC/DHPC with 6:1 mole ratio was investigated in the temperature range of 10-75 degrees C using (31)P, (2)H, and (23)Na NMR. At lower temperatures (10-54 degrees C), the system is dominated by the bicellar phase. At higher temperatures (54-75 degrees C), isotropic micelles are formed and coexist with the bicelles. The partial alignment of maltotriose in the DBBPC/DHPC system was studied at three temperatures, and the (1)H-(13)C dipolar coupling constants are compared with those obtained for two other bicelle solutions.
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Affiliation(s)
- Chibing Tan
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK 73019-3051, USA
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Fung BM, Mamrosh DL, O'Rear EA, Frech CB, Afzal J. Unusual micellar properties of a new class of fluorinated nonionic surfactants. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100326a032] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Liu SB, Fung BM, Yang TC, Hong EC, Chang CT, Shih PC, Tong FH, Chen TL. Effect of Cation Substitution on the Adsorption of Xenon on Zeolite NaY and on the Xenon-129 Chemical Shifts. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100067a030] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Guo W, Li Z, Fung BM, O'Rear EA, Harwell JH. Hybrid surfactants containing separate hydrocarbon and fluorocarbon chains. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100195a038] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Kong CF, Holloway GM, Parhami P, Fung BM. Carbon-13 and fluorine-19 nuclear magnetic resonance study of perfluoro chemical emulsions. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j150669a050] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Afzal J, Ashlock SR, Fung BM, O'Rear EA. Interaction between perfluoro chemicals and oxygen in phosphatidylcholine vesicles. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100404a045] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Abstract
The isotropic chemical shift and the nuclear quadrupole coupling constant for (14)N were obtained for 14 inorganic nitrates by solid-state MAS NMR measurements at two different field strengths, 9.4 and 11.7 T. The compounds studied were polycrystalline powders of AgNO(3), Al(NO(3))(3), Ba(NO(3))(2), Ca(NO(3))(2), CsNO(3), KNO(3), LiNO(3), Mg(NO(3))(2), NaNO(3), Pb(NO(3))(2), RbNO(3), Sr(NO(3))(2), Th(NO(3))(4)center dot4H(2)O, and UO(2)(NO(3))(2)center dot3H(2)O. Even though the spectra show broadening due to (14)N quadrupole interactions, linewidths of a few hundred hertz and a good signal-to-noise ratio were achieved. From the position of the central peaks at the two fields, the chemical shifts and the nuclear quadrupole coupling constants were calculated. The chemical shifts for all compounds studied range from 282 to 342 ppm with respect to NH(4)Cl. The nuclear quadrupole coupling constants range from 429 kHz for AgNO(3) to 993 kHz for LiNO(3). These data are compared with those available in the literature.
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Affiliation(s)
- Simon P Marburger
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73019-3051, USA
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Abstract
The use of indirect detection for signal enhancement in solids is much less common than in liquids, but has attracted renewed interest recently. In this work we describe an indirect detection scheme that offers a large signal enhancement for rare spins in solids. The method uses multiple periods of cross polarization, each followed by an evolution period. The latter is increased stepwise in a pseudo 2D experiment, in which the signal of the rare spin is detected as modulation of the abundant spin. As an illustration of this method, the natural abundance deuterium NMR spectrum of a static powder sample of 1,2,4,5-tetramethylbenzene is presented.
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Affiliation(s)
- A K Khitrin
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73019-0370, USA
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Khitrin AK, Canlet C, Fung BM. Filtering of spinning sidebands in 1D MAS NMR spectra. Solid State Nucl Magn Reson 2001; 19:63-72. [PMID: 11508806 DOI: 10.1006/snmr.2001.0021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Spinning sidebands (SSBs) in the MAS NMR spectrum of a polycrystalline solid are related to the principal values of the chemical shift or quadrupole coupling tensors. At present, 2D methods are widely used to sort out the SSBs for each isotropic peak. Here a simple and efficient method for separating the SSBs in 1D MAS NMR spectra is described. It is based on finding the optimal spinning rate with a mathematical algorithm and subsequently treating the spectra with filtering functions.
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Affiliation(s)
- A K Khitrin
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman 73019-0370, USA
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Affiliation(s)
- G Cho
- Department of Chemical Engineering, Sunchon National University, 315 Maegok Sunchon, Chonnam 540-742, Korea
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Zhang C, Song Y, Fung BM, Xin X, Xue Z. A new approach to superior optical limiting materials—planar ‘open’ heterothiometallic clusters. Chem Commun (Camb) 2001. [DOI: 10.1039/b100395j] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Affiliation(s)
- Cécile Canlet
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73019-0370
| | - B. M. Fung
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73019-0370
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Abstract
Recently we developed an efficient broadband decoupling sequence called SPARC-16 for liquid crystals ¿J. Magn. Reson. 130, 317 (1998). The sequence is based upon a 16-step phase cycling of the 2-step TPPM decoupling method for solids ¿J. Chem. Phys. 103, 6951 (1995). Since then, we have found that a stepwise variation of the phase angle in the TPPM sequence offers even better results. The application of this new method to a liquid crystalline compound, 4-n-pentyl-4'-cyanobiphenyl, and a solid, L-tyrosine hydrochloride, is reported. The reason for the improvement is explained by an analysis of the problem in the rotating frame.
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Affiliation(s)
- B M Fung
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73019-0370, USA
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Khitrin AK, Fung BM. 14N nuclear magnetic resonance of polycrystalline solids with fast spinning at or very near the magic angle. J Chem Phys 1999. [DOI: 10.1063/1.480239] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Fung BM, Bräuniger T. Comment on “Monte Carlo simulations of smectic phase transitions in flexible-rigid-flexible molecules” [J. Chem. Phys. 110, 12183 (1999)]. J Chem Phys 1999. [DOI: 10.1063/1.480258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Abstract
The effect of several new homonuclear dipolar decoupling methods (frequency-switching Lee-Goldburg decoupling and two sequences based on z-rotational decoupling) on the 13C spectra of liquid crystals has been studied, and the results are compared with those obtained by using two well-established methods (MREV-8 and BLEW-48). For benzene dissolved in two liquid crystalline solvents, BLEW-48 gives the best spectral resolution. The BLEW-48 sequence has also been applied to the 2D method of proton-encoded local field (PELF) spectroscopy to study a bulk liquid crystal, 4-n-pentyl-4'-cyanobiphenyl (5CB). The results are compared with those obtained by using MREV-8, and it is suggested that the BLEW-48 sequence may be preferable to MREV-8 for application in the PELF method. Copyright 1999 Academic Press.
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Affiliation(s)
- BM Fung
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, 73019-0370, USA
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