36-phase cycling for two-pulse ±3Q-MAS
[an error occurred while processing this directive]Two-pulse MQ-MAS with 36-phase cycling
M. Hanaya and R. K. Harris [J. Phys. Chem. A, 101, 1903-1910 (1997)]
solved the system of two equations for the receiver phase in the two-pulse, ±3Q-MAS
sequence:
φrec = +3*φ1 - 2*φ2,
φrec = -3*φ1 + 4*φ2.
(1) 36-phase cycling
The solution to this is both pulse phases take six values: 0°, 60°, 120°, 180°, 240°, and 300°.
| φ1 = | 0° 60° 120° 180° 240° 300° |
|---|---|
| φ2 = | {0°}X6 {60°}X6 {120°}X6 {180°}X6 {240°}X6 {300°}X6 |
| φrec = | {0° 180°}X3 {240° 60°}X3 {120° 300°}X3 |
Since the receiver phase takes values different from 0°, 90°, 180°, and 270°, this 36-phase cycling is applied scarcely [J. Skibsted and H. J. Jakobsen, J. Phys. Chem. A, 103, 7958-7971 (1999)].
(2) Simulation
We provide SIMPSON1.1.1 Tcl scripts for simulating the echo and antiecho
amplitude versus a pulse duration:
(1) filtering the coherences,
(2) 36-phase cycling the pulses and the receiver.
| Duration | Filtering | 36-phase cycling |
|---|---|---|
| 1st-pulse | na-filtering-p1 | na-36-cycling-p1 |
| 2nd-pulse | na-filtering-p2 | na-36-cycling-p2 |
(3) Result
When the amplitudes are normalized to the number of phase cycling, these two approaches provide the same simulation data about echo and antiecho amplitude for spin I = 3/2, 5/2, and 7/2 systems.
(top)