NMR Spectra Simulator SPECSIM

Guido Kopal and Stefan Langenberg
University of Bonn

A contribution to EASA 1994

SPECSIM is designed to calculate second order H-NMR spectra. The calculated spectra can be displayed on screen or printed on several printers. Systems with up to 6 spins can be handled by SPECSIM.


Change to the drive, from which you want to install SPECSIM, e.g. type a: [ENTER]. Start the installation program by typing setup [ENTER]. Select your preferred language and the target directory in the setup program. Then the SPECSIM files are copied to your hard-disk.

Change to your SPECSIM directory, e.g. cd \specsim [ENTER]. Start SPECSIM by typing spec [ENTER]


SPECSIM is used to calculate first and second order high resolution NMR spectra for spin 1/2 nuclei. The spectra are calculated from chemical shifts, spin-spin coupling constants and the conditions of spectra acquisition (NMR frequency and line-widths). SPECSIM sets up the Hamiltonian matrix of the entered spin system. The NMR line positions are the eigenvalues of this matrix, they are calculated by Householder tridiagonalisation. The intensities of the NMR lines are calculated from the eigenvectors of the Hamiltonian matrix. The calculated spectra can be displayed on several graphics adapters and printers. Printers already supported are HP-LaserJet, HP-DeskJet, NEC P6, Epson LQ and compatibles. Due to memory limitations, SPECSIM only handles systems with up to 6 spins.

Since SPECSIM is supplied with Borland's TurboVision user interface, simple user control by mouse and keyboard is possible. SPECSIM is menu driven, all parameters are entered in dialog boxes. Unreasonable user inputs are rejected. An on-line help to all menu items is available. The colours of the user interface can be freely configured. Changes of the user interface can be saved in the CONFIG.CFG file. They are available in the next session. The installation of SPECSIM is supported by a setup program.

SPECSIM is designed for students learning NMR spectroscopy and for research chemists. This program allows students to make simple simulation experiments, accompanying a course in NMR spectroscopy. They can investigate the spectra of frequent occurring spin systems, like AX, AB... Furthermore the transition of a spectrum from first to second order can be studied, for example, depending on the NMR spectrometer frequency. In addition spin systems like AA'BB' can be studied, which are never of first order. SPECSIM may be used by chemists, who want to identify an unknown compound by NMR spectroscopy. The spectra of several hypothesised structures can be calculated by SPECSIM. These spectra are visual compared with the recorded spectrum. In addition SPECSIM may be used to estimate chemical shift values and spin spin coupling constants from a second order spectrum. Although iteration of spin systems is not possible with SPECSIM, these parameters can be estimated by manually refining the simulation parameters.

Because SPECSIM has been finished close to the deadline, the program has not been employed in education. This is intended for the future.

SPECSIM is already supplied with menus and on-line help in German and in English. The desired language is selected during installation. Adaptation of SPECSIM to other languages is possible, recompilation of SPECSIM is not necessary. Help messages and menu text of the user interface are stored in separate files. HELP.HLP is the english help text file, HILFE.HLP is the german file. The file HOTHER.HLP is provided for help text in another language. English and german menu entries are stored in the STRINGS.RES file. All these files can be modified by the user. The files HELP.TXT (in English) and HILFE.TXT (in German) contain the source code of the .HLP files. SPECSIM is translated to another language as follows: select the option 'other language' in the setup program during installation. Next translate the source file HOTHER.TXT. Generate a new HOTHER.HLP file by using the utility program MAKEHELP.EXE, which is supplied on the installation disk. Example: to generate a new HOTHER.HLP file from the source file HOTHER.TXT, type

Replace HOTHER.HLP with your new one. The menu entries are translated in a much similar way. They are stored in the STRINGS.RES file. This file was created using MAKESTR.PAS. Translate the strings in MAKESTR.PAS to your desired language and compile it with Borland Pascal 7.0 to generate a new STRINGS.RES file. Replace the old STRINGS.RES file with your new one.

In contrast to more powerful NMR simulation programs, e.g. WIN-DAISY (Bruker Franzen Analytik, Bremen / University of Duesseldorf), SPECSIM is public domain. Furthermore only a minimum of hardware and no additional software is required to run SPECSIM.

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Stefan Langenberg, Sat Apr 26 16:03:34 2003