ICON-EDiT

an Extended-Hückel and
Oscillator Strength Calculation
Package

by Gion Calzaferri, Ruedi Rytz, and Martin Brändle
Department of Chemistry and Biochemistry
University of Bern
Freiestrasse 3, 3012 Bern, Switzerland

Copyright by the Authors

What is ICON-EDiT?

What does the distribution contain?

How do I install the package?

How do I run ICONC?

How do I run EDiT?

What are the requirements of your PC?

Tips and Tricks

What is ICON-EDiT?

ICON-EDiT is a FORTRAN program package that performs extended-Hückel and oscillator strength calculations on molecules.

s,p,d orbitals, a two-body repulsive energy term, different Wolfsberg-Helmholz formulas, charge iteration procedures, geometry variation and an FMO option are included.

ICON-EDiT consists of four parts, INPUTC, ICONC, EDiT and GOP.

INPUTC
This part of the package is a self-explanatory input program. It reads the necessary parameters such as the valence orbital ionization energies (VOIEs), the Slater-type orbitals (STOs) as well as the charge-iteration parameters from the ASCII data files ATOMDEF.DAT, VOI.DAT and FOI.DAT in order to generate the file SOMENAME.KAR (Cartesian coordinates) or SOMENAME.GEN (internal coordinates with geometry variation). As ICONC is designed to work with Cartesian coordinates, the previously generated internal coordinate file SOMENAME.GEN can be converted to a Cartesian file named TEMP.KAR (cf. INPUTC Option #3). The parameter files may be extended and/or adapted to meet the requirements of the user.

ICONC
performs extended-Hückel calculations on files created by INPUTC.

EDiT
allows to calculate oscillator strengths of electronic dipole-induced transitions (EDiTs) based on Slater-type extended-Hückel wave functions.

GOP
searches for a minimum in an energy hyper surface using INPUTC and ICONC.

ICON-EDiT runs on PC, VAX, IBM RISC and many more. No machine specific specialties have been included.

What does the distribution contain?

PROGRAMS

PARAMETER FILES

INPUT FILES

Some ready to use example files are

OUTPUT FILES

Some of the output files you may use for comparison are

How do I install the package?

If you plan to use the programs under Windows 3.x (DOS Shell) you should install the 32-bit extender program DOSXNT.386 by adding the line

DEVICE=C:\ICONEDIT\DOSXNT.386

to the [Enh386] section of your SYSTEM.INI file. If you wish to copy the files to different directories to meet your requirements you are encouraged to do so. However, make sure that the 32-bit DOS extender DOSXMSF.EXE can be loaded and do not forget that INPUTC needs to open ATOMDEF.DAT, VOI.DAT and FOI.DAT. EDiT will use the files SOMENAME.GEN, SOMENAME.MO and SOMENAME.EDI as its input.

Remember that updated versions of the program package are only available for Windows NT.

How do I run ICONC?

For input files that are already in Cartesian coordinates (files with the extension KAR) simply type at the command prompt

ICONC < SOMENAME.KAR > SOMENAME.OUT

(If you wish to keep the distributed output files for comparison make sure you do not overwrite them by choosing a different name.)

ICONC will read the input from SOMENAME.KAR. Its output will be written to stdout (the standard output device). You may wish to redirect it to a file ( > SOMENAME.OUT).

Input files that are in internal coordinates have to be converted to Cartesian coordinates prior to running ICONC. You do this with INPUTC. Type INPUTC at the command prompt and choose option #3. Follow the instructions of the program. If you are done you should notice two new files in your working directory, namely TEMP.KAR and TEMP.VAR. (The TEMP.VAR file is written to check that geometry variation has succeeded, you needn't care for the moment.) Then type

ICONC < TEMP.KAR > SOMENAME.OUT

How do I run EDiT?

In order to run EDiT you need to have the file SOMENAME.EDI, which can be written with the ICONC program by choosing the appropriate output option in the INPUTC program. To do so answer the question in INPUTC "Do you want to define additional parameter? [N]" with Y. Choose option #2 "Controlling output options". Oscillator strength calculation output is then requested by choosing #23. Now you are ready to run ICONC as described in section 4. The newly generated file SOMENAME.EDI has to be prepared separately with an ASCII editor. Check the file MnO4-.EDI in this distribution and comments made therein to get an overview of possible KEYWORDS that are controlling EDiT output. Run the program from the command prompt by typing

EDiT.bat SOMENAME

(Note: On DOS Machines the name EDiT may interfere with the DOS EDITOR, you may wish to rename EDiT to EDiTOR, Electronic Dipole-induced Transitions by Slater-type ORbitals.)

What are the requirements of your PC?

ICON-EDiT runs on PC i386 and higher. As all declared data must load into memory at startup, a compromise between the desire to treat as large systems as possible and the memory requirement had to be made. We decided to compile ICON-EDiT for 100 atoms and 400 AOs. This allows to run the program on a machine with 16 Mb of built-in RAM without needing to access virtual memory. If you have less RAM available it is still possible to run ICON-EDiT by allowing the program to page out parts of the memory to the hard disk (pageing). Virtual memory management is considerably different under DOS and Windows. Under DOS the virtual memory is managed by Phar Lap DOS extender. Disk space will be used on the drive where DOSXMSF.EXE is located. This will NOT WORK on a compressed drive. Hence, if you use DriveSpace you will have to relocate your swap file by adding something like

SET DOSX=-SWAPDIR X:\TMP

to AUTOEXEC.BAT. If you run the programs under Windows 3.x in a DOS shell, Windows will take care of your swap file. HOWEVER, WE STRONGLY RECOMMEND NOT TO USE THE PROGRAMS WITHIN Windows 3.x.

ICON-EDiT Home Page