2D Double Quantum & Multiple Quantum COSY Experiments

Variations of the DQCOSY experiment

Higher orders of quanta may be used to filter the COSY experiment . Type mqcosy and change the following parameters from the standard DQCOSY parameters:

qlvl = level of quantum filtration

nt = multiple of 2*qlvl

Acquiring the experiment:

1. Join the experiment in which the ¹H reference spectrum was collected. Type dqcosy.

2. Type dg. Adjust the parameters listed below for the standard DQCOSY:

sfrq=399.879 dm='n'

tn=H1 sw1 = sw from ¹H reference spectrm

at = set by spectrometer ni = multiple of 64

np=2048 phase=1,2

sw = sw from ¹H reference spectrum dp='n'

ss=2 hs='n'

tpwr = listed at console sspul='n'

pw = ¹H 90° pulse width

p1=0

d1 = ¹H relaxation delay (1-2 * ¹H T₁)

d2=0 rf1 = rf from ¹H reference spectrum

presat=0 rfp1 = rfp from ¹H reference spectrum

tof = tof from ¹H reference spectrum wp1 = wp from ¹H reference spectrum

nt = multiple of 4 sp1 = sp from ¹H reference spectrum

Change ni, nt, and d1 to suit your scheduled time. The vertical (non-acquisition) resolution equals sw1/2ni. Typical values are listed below for sw1=4400:

d1	ni	nt	time	vert. res	d1	ni	nt	time	vert. res
1.5	128	4	0:30	17.2 Hz	1.5	128	64	8:07	17.2 Hz
1.5	256	4	1:01	8.6	1.5	256	64	16:21	8.6
1.5	512	4	2:05	4.3	1.5	512	64	33:14	4.3
1.5	128	16	2:02	17.2	2.25	128	4	0:43	17.2
1.5	256	16	4:05	8.6	2.25	256	4	1:27	8.6
1.5	512	16	8:18	4.3	2.25	512	4	2:56	4.3

Processing, Displaying, and Plotting:

Process using the procedure for Processing a 2D Phase-Sensitive Experiment. Plot All Contours. The DQCOSY spectrum may be symmeterized by typing foldt.