This approach identifies the correct spectrum in all cases and excludes approximately 80% of the incorrect spectra, demonstrating that an automated search of theoretical libraries of spectra may eventually become feasible. An automated approach for comparing spectra is also described that minimizes residuals between a given theoretical spectrum and all available experimental spectra. A comparison of computed spectra in the gas phase indicates that the inclusion of n-octane shifts peaks by +11 nm on average and this change is roughly equivalent for PBE0 and CAM-B3LYP. Download Gaussian The following download links are password protected. It provides state-of-the-art capabilities for electronic structure modeling. Gaussian 16 is the latest in the Gaussian series of programs.
#Gaussian software vs hyperchem 64 Bit
These calculated spectra can be empirically corrected to decrease the uncertainties to 6.5 ± 5.1 and 5.7 ± 5.1 nm for the PBE0 and CAM-B3LYP methods, respectively. Gaussian 64 bit download - X 64-bit Download - 圆4-bit download - freeware, shareware and software downloads. Specifically, when solvent is included the PBE0 functional overestimates peaks by 16.1 ± 6.6 nm while CAM-B3LYP underestimates the same transitions by 14.5 ± 7.6 nm. All theoretical spectra visually conform to the profiles of the experimental data but are systematically offset by a small amount. Unusually high-resolution experimental spectra are obtained for comparison by analyzing each PAH at 4.2 K in an n-alkane matrix. Spectra for several of the most toxic PAHs are predicted and compared to experiment, including three isomers of C 24H 14 and a PAH containing heteroatoms. Two methods, PBE0 and CAM-B3LYP, are evaluated both in the gas phase and in solution.
The ability of density functional theory (DFT) methods to predict accurate fluorescence spectra for polycyclic aromatic hydrocarbons (PAHs) is explored.
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