Selectivity in multiple quantum nuclear magnetic resonance

Thesis/Dissertation · Sat Nov 01 00:00:00 EST 1980

DOI:https://doi.org/10.2172/7091703· OSTI ID:7091703

Warren, Warren Sloan ^[1]

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1. Univ. of California, Berkeley, CA (United States). Dept. of Chemistry; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Sciences Division

The observation of multiple-quantum nuclear magnetic resonance transitions in isotropic or anisotropic liquids is shown to give readily interpretable information on molecular configurations, rates of motional processes, and intramolecular interactions. However, the observed intensity of high multiple-quantum transitions falls off dramatically as the number of coupled spins increases. The theory of multiple-quantum NMR is developed through the density matrix formalism, and exact intensities are derived for several cases (isotropic first-order systems and anisotropic systems with high symmetry) to shown that this intensity decrease is expected if standard multiple-quantum pulse sequences are used. New pulse sequences are developed which excite coherences and produce population inversions only between selected states, even though other transitions are simultaneously resonant. One type of selective excitation presented only allows molecules to absorb and emit photons in groups of n. Coherent averaging theory is extended to describe these selective sequences, and to design sequences which are selective to arbitrarily high order in the Magnus expansion. This theory and computer calculations both show that extremely good selectivity and large signal enhancements are possible.

• Research Organization: Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 7091703
• Report Number(s): LBL-11885; TRN: 81-002451
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
NUCLEAR MAGNETIC RESONANCE
HAMILTONIANS
QUANTUM MECHANICS
BENZENE
COMPUTER CALCULATIONS
ENERGY-LEVEL TRANSITIONS
FOURIER TRANSFORMATION
MOLECULES
PULSE TECHNIQUES
SPIN
T INVARIANCE
ZEEMAN EFFECT
ANGULAR MOMENTUM
AROMATICS
HYDROCARBONS
INTEGRAL TRANSFORMATIONS
INVARIANCE PRINCIPLES
MAGNETIC RESONANCE
MATHEMATICAL OPERATORS
MECHANICS
ORGANIC COMPOUNDS
PARTICLE PROPERTIES
QUANTUM OPERATORS
RESONANCE
TRANSFORMATIONS
656000* - Condensed Matter Physics