| Autor: |
Ido Azuri, Anna Hirsch, Anthony M. Reilly, Alexandre Tkatchenko, Shai Kendler, Oded Hod, Leeor Kronik |
| Jazyk: |
angličtina |
| Rok vydání: |
2018 |
| Předmět: |
|
| Zdroj: |
Beilstein Journal of Organic Chemistry, Vol 14, Iss 1, Pp 381-388 (2018) |
| Druh dokumentu: |
article |
| ISSN: |
1860-5397 |
| DOI: |
10.3762/bjoc.14.26 |
| Popis: |
We present a computational analysis of the terahertz spectra of the monoclinic and the orthorhombic polymorphs of 2,4,6-trinitrotoluene. Very good agreement with experimental data is found when using density functional theory that includes Tkatchenko–Scheffler pair-wise dispersion interactions. Furthermore, we show that for these polymorphs the theoretical results are only weakly affected by many-body dispersion contributions. The absence of dispersion interactions, however, causes sizable shifts in vibrational frequencies and directly affects the spatial character of the vibrational modes. Mode assignment allows for a distinction between the contributions of the monoclinic and orthorhombic polymorphs and shows that modes in the range from 0 to ca. 3.3 THz comprise both inter- and intramolecular vibrations, with the former dominating below ca. 1.5 THz. We also find that intramolecular contributions primarily involve the nitro and methyl groups. Finally, we present a prediction for the terahertz spectrum of 1,3,5-trinitrobenzene, showing that a modest chemical change leads to a markedly different terahertz spectrum. |
| Databáze: |
Directory of Open Access Journals |
| Externí odkaz: |
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