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Universität Hamburg Fachbereich Chemie



This software is in active developement! Please report any bugs, errors, bad spelling, etc. to the author.


When learning or teaching the physics behind the nuclear magnetic resonance (NMR) experiment one has to deal with several quantum mechanical models that become more and more abstract as the scholar advances in the subject. Most classes start with the relatively simple vector model, which inevitably fails with the simplest two-dimensional techniques like COSY. A more complete model is the product operator formalism, which in turn is based on the density matrix approach of statistical quantum mechanics.

This software simulates the NMR experiment by visualizing all three models mentioned above. The user can interact with every step of the spectrum from the first pulse to the phase correction of the acquired spectrum after Fourier transformation.

Insensitive (Incredible Nuclear Spin EvolutioN SImulation Tool Intended for Visual Education) comes with a tutorial that explains the concepts of modern NMR and includes a step-by-step analysis of many pulse programmes. While other NMR applications simulate a virtual spectrometer (VSNMR, MestRe-S), are only available as part of expensive sortware suites (Bruker TopSpin 3.0) or already require knowledge of NMR and a programming language (Gamma, mPackages, Spinach) Insensitive focuses on the visualization of textbook NMR theory.

Insensitive is intended for education or self education in NMR at an intermediate level. It does not teach how to interpret spectra, and it does not try to teach or implement state-of-the-art simulation algorithms. A basic understanding of quantum mechanics (or the willingness to tackle the field) is recommended. Although the tutorial introduces the basic concepts it is not intended as a textbook of its own. The author recommends the textbook Spin Dynamics by Malcolm H. Levitt and Understanding NMR Spectroscopy by James Keeler as a companions for using Insensitive.

A paper on Insensitive has been published in Concepts in Magnetic Resonance Part A. If you use the program or parts thereof in publications or presentations, please cite K. Boldt, Conc. Magn. Reson., 2011, 38A (2), 17-24. The legacy version (0.9.5) discussed in the paper can be downloaded here.

Concerning Insensitive for Windows

I have been approached by several users to release Insensitive for Windows or Linux. I would love to support other platforms, but since Insensitive has been written in Objective-C and now includes about 20.000 lines of code this is a big project. There are two possible toolkits to port Insensitive, GNUstep and The Cocotron. Cocotron seems to be the choice for user-friendliness, but Apple's Accelerate framework for matrix algebra and FFT (BLAS, LAPACK and vDSP) is not yet easily available. If anybody has knowledge of either system and wants to help, please contact me!

Recent Changes

New in version 0.9.14: A new presentation mode for lectures, open and save spectra, save current spin state in spin system files, apodisation by gaussian pseudo-echo transformation, select gyromagnetic ratios for I and S spins, only display relevant channels in the pulse sequence, rotate spin system, bugfixes and additions to the tutorial.

New in version 0.9.11: Improved energy level diagrams with correct labels for strongly coupled systems, experimental support for coherence pathway diagrams, Insensitive can be forced to English localisation, bugfixes and additions to the tutorial.

New in version 0.9.10: Spin lock and ROE, labels for pulse sequences, editing pulses, delays and gradients in pulse sequences, contour plots for 2D spectra, export spectra and pulse programs as ASCII data, automatic updates using Sparkle, new preferences window, detection threshold for acquisition, bugfixes, additions to the tutorial.

New in versuon 0.9.9: States and TPPI methods for amplitude modulated 2D spectra, gaussian pulse shapes, "Remove Spin" now deletes the selected spin instead of the one with the highest index, quick access menu for common pulses, collapsing settings panels, additions to the tutorial, bugfixes.

New in version 0.9.8: Bugfixes.

New in version 0.9.7: Insensitive has been written from scratch since the last version. Additions include pulsed field gradients, record and play pulse sequences, phase cycling, acquisition of 2D spectra, graphical matrix display, display of dipolar coupling constants and distances in the Spin Network Editor, open and save spin systems and pulse sequences, select predefinded delay times, additions to the tutorial and bugfixes.


Dr. Klaus Boldt
University of Melbourne
School of Chermistry & Bio21 Institute
Level 2 North, 30 Flemington Road
Parkville, VIC 3010

Email: klaus.boldt (at)

System Requirements
Mac OS X 10.5.0 or later

Download Details
Version: 0.9.14
Post Date: April 27, 2013
License: MIT License
File Size: 58.5 MB
Source code: download

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