Multiple quantum correlated spectroscopy revamped by asymmetric z-gradient echo detection signal intensity as a function of the read pulse flip angle

Bin Jiang, Huili Liu, China Maili Liu, Chaohui Ye, and China Xi-an Mao
J. Chem. Phys. 126, 054502 (2007)

(Received 28 August 2006; accepted 5 December 2006; published online 1 February 2007)

Heteronuclear multiple quantum (n=±0 and n=±2) correlated spectroscopy revamped by asymmetric z-gradient echo detection (CRAZED) experiments were performed on the spins ³¹P and ¹H in a H₃PO₄ solution in order to determine the optimum flip angle for the read pulse. It has been shown that for the negative quantum signals, the maximum signals appear at =0, and for the positive quantum signals, the maximum signals appear at =. The CRAZED signals were compared to the single quantum signals in two-pulse two-gradient experiments. It is found that the CRAZED signals can also be distinguished into gradient echoes and spin echoes. The gradient-echo-type CRAZED signal requires =0 and the spin-echo-type CRAZED signal requires = for maximum echo intensities, in the same way as in single quantum experiments. ©2007 American Institute of Physics