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NICS-scan (J. Org. Chem. 2006, 71, 883-893), the σ-only model (J. Org. Chem. 2010, 75, 2281-2288) and the NICS-XY-scan (Chem. Eur. J., 2014, 20, 5673-5688)
are useful methods to determine the presence of diatropic and paratropic ring currents (aromaticity and antiaromaticity), local and global.
Aroma is a plugin package that has been written by Dr. Anuja Rahalkar (a post-doctoral fellow in my group) that automates these procedures for using with the Gaussian software package.
Using Aroma circumvents the need to manually build the appropriate input files and saves the user the difficulty of manually handling vast amounts of numerical data, making the use of the NICS-scan, the σ-only model and NICS-XY-scan easy and accessible.
Aroma 1.0 accepts standard Gaussian input, output or checkpoint files as input. It has also the possibility to accept a non-standard input file (see the manual).
It can automatically perform (on request) geometry optimization and a frequencies calculation.
It automatically generates an input NICS-scan file for user-defined rings (and bonds and atoms in the case of NICS-XY-scan) using a user-defined BQ range and step size (defaults are 0-3.9 Å and 0.1 Å, respectively), as well as σ-only input files, and subsequently runs the appropriate Gaussian jobs.
In addition to the standard Gaussian output files, Aroma generates text files that contain all the NICS-scan data, and, if NCS and/or σ-only model procedures are requested, also text files that contain the π-MOs contributions to each of the BQs’ chemical shifts and the NICS-scan results for the model.
These files can be read by standard software (such as MS-Excel, OriginLab) for the analyses.
Finally, a text file, containing the results of the analysis according to 3rd degree polynomial fit and the calculation of the chemical shift (NICS(1)p,ZZ value) for each of the rings is provided.
Aroma is available as the source code that needs Python interpreter and several other libraries or as a stand-alone binary version, for Linux, windows and Mac-OS.
The manual, including installation instructions, is available for download here.
To download a Linux-compatible and a Mac-compatible version (source and/or binary) click here.
To download a Windows 7-compatible version (source and/or binary) click here.