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Messages - MalcolmHLevitt

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16
Examples / Re: Chemical exchange in an AB system
« on: July 18, 2016, 01:44:18 PM »
Hi Andy,
 thanks for this. Just as for the AB case I posted, handling chemical exchange (as required for CPMG on a chemically exchanging system) entirely within SpinDynamica is currently not possible, although the necessary package extension is thoroughly feasible and the necessary functionality has long been planned. The problem is time and manpower. The existence of a strong demand is a very good stimulus but I am simply too busy to promise it in a short timeframe. If anyone is out there who feels sufficiently motivated to take on a programming task of this kind, I am very willing to help them.
 So although a general implementation of multisite chemical exchange in SpinDynamica is still some way off, programming a task-specific piece of code (as I did for the AB example) is more feasible. However, once again, my lack of time makes it hard to do this without additional help.
 sorry for this discouraging news
malcolm

17
Updates and Messages / Add-Ons
« on: March 18, 2016, 03:06:47 PM »
Two add-on packages have been posted on the SpinDynamica website http://www.spindynamica.soton.ac.uk/about/addons/:

SymmetryBasedRecouplingAnalysis is a resurrection of the old routines CandRsymmetries which allows calculation of selection rules and scaling factors for symmetry-based recoupling sequences.

PolarizationOperator is a new symbol which may be used to derive the level of polarization of a single spin or set of spins, from an arbitrary density operator.

18
Updates and Messages / SpinDynamica 2.14.2 released
« on: February 07, 2016, 09:50:47 AM »
SpinDynamica 2.14.2 has been released here:
https://www.dropbox.com/sh/6io3s1ub8j4lgoa/AABIK7LT7mZaEb-s4DjvmY1la?dl=0

It includes some important bug fixes.

19
Examples / Re: Product operator calculations
« on: December 21, 2015, 10:40:41 PM »
Hi Jean-Nicolas,
 The timing issues you raise should have been addressed in v2.14.1
malcolm

20
Publications / Quantum-rotor-induced polarization
« on: December 20, 2015, 01:07:55 PM »
The paper

S.S. Roy, J.-N. Dumez, G. Stevanato, B. Meier, J.T. Hill-Cousins, R.C.D. Brown, et al., Enhancement of quantum rotor NMR signals by frequency-selective pulses, J. Magn. Reson. 250 (2015) 25–28. doi:10.1016/j.jmr.2014.11.004.

uses SpinDynamica to treat quantum-rotor-induced polarization and predict enhancements generated by frequency-selective pulses.

21
Publications / Long-lived states in 4-spin systems
« on: December 20, 2015, 01:05:48 PM »
The paper

G. Stevanato, S. Singha Roy, J. Hill-Cousins, I. Kuprov, L.J. Brown, R.C.D. Brown, et al., Long-lived nuclear spin states far from magnetic equivalence, Phys. Chem. Chem. Phys. 17 (2015) 5913–5922. doi:10.1039/C4CP05704J.

uses SpinDynamica to analyze long-lived states in 4 spin systems, using the matrix representations of operators in symmetry-adapted bases to pick out the essential features of the spin dynamics.

22
The paper:

P.W. Kuchel, D. Shishmarev, M. Puckeridge, M.H. Levitt, C. Naumann, B.E. Chapman, NMR of 133Cs+ in stretched hydrogels: One-dimensional, z- and NOESY spectra, and probing the ion’s environment in erythrocytes, Journal of Magnetic Resonance. 261 (2015) 110–120. doi:10.1016/j.jmr.2015.10.011.

includes some explicit SpinDynamica code descriptions.

23
Hi Evan, this bug has been fixed in the latest SpinDynamica release 2.14.1
malcolm

24
Hello Riddhiman, this bug has been fixed in the latest release (2.14.1)
malcolm

25
Updates and Messages / SpinDynamica 2.14.1 released
« on: December 20, 2015, 12:47:40 PM »
SpinDynamica 2.14.1 has been released here:
https://www.dropbox.com/sh/r922kdcndxr0xgf/AAAdNEZ4n7Zm0d2QOaimWVH6a?dl=0

Includes bug fixes, enhanced documentation, and speed enhancements.

26
Thanks Evan,
 I'm sorry for taking so long to notice this bug report. I will add it to my list of tasks.

 Unfortunately I now have little time to attend to SpinDynamica.

best wishes
malcolm

27
Thanks Riddhiman,
 apologies for the delay in replying.

 I will add this to my list of tasks.

 Unfortunately I currently have little time to attend to SpinDynamica.

best wishes
malcolm

28
Examples / Re: Product operator calculations
« on: June 05, 2015, 09:31:51 AM »
Hi Jean-Nicolas,
 I have looked at this and while temporary fixes are possible I prefer to do some more major restructuring to avoid the repeated and time-consuming pattern matching loops which are responsible for this slow execution of symbolic code for more than a very small number of spins. I will get round to this but it may take some time. In the meantime please do use the shortcut you found.
 sorry for the delay
malcolm

29
Examples / Product operator calculations
« on: May 28, 2015, 05:34:50 PM »
I get quite a few queries asking how one can do product operator calculations for weakly coupled systems using SpinDynamica. I attach a file showing a few examples, including INADEQUATE in a 2-spin-1/2 system and INEPT in an A3X system.

The file also includes a product operator calculation for spin-3/2. Such calculations are not easy to do by hand.

30
Updates and Messages / SpinDynamica 2.13.1 released
« on: May 27, 2015, 08:48:36 AM »

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