Experiments on selective excitation of multiple-quantum transitions in NMR spectroscopy

Journal Article · Sun Mar 01 00:00:00 EST 1981 · J. Chem. Phys.; (United States)

DOI:https://doi.org/10.1063/1.441452· OSTI ID:6564944

Warren, W S; Pines, A

Irradiating a spin system with an appropriate sequence of phase shifted pulses excites only certain orders of multiple-quantum transitions excited. Using such sequences in preparation and detection produces a large signal/noise enhancement for the multiple-quantum spectra over nonselective excitation, as predicted from theory. In a previous paper the theory was presented in detail. In this paper some aspects of the theory are first outlined briefly. Experimental results are then presented demonstrating four-quantum, six-quantum, and A-symmetry selection in oriented benzene and eight-quantum selection in oriented 1-bromobutane. A six-quantum selective sequence applied to benzene with nonequilibrium initial reduced density matrix proportional to I/sub x/ produces one- and five-quantum spectra. The n-quantum signal/noise enhancements are obtained and the selectivity is measured as a function of pulse sequence parameters. The behavior is that expected if one assumes that the limit to selectivity is determined by leading nonselective terms in an average Hamiltonian expansion.

• Research Organization: Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
• OSTI ID: 6564944
• Journal Information: J. Chem. Phys.; (United States), Vol. 74:5
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
BENZENE
NMR SPECTRA
BROMINATED ALIPHATIC HYDROCARBONS
FORBIDDEN TRANSITIONS
SPIN ORIENTATION
AROMATICS
ENERGY-LEVEL TRANSITIONS
HALOGENATED ALIPHATIC HYDROCARBONS
HYDROCARBONS
ORGANIC BROMINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORIENTATION
SPECTRA
640302* - Atomic
Molecular & Chemical Physics- Atomic & Molecular Properties & Theory