| Autor: |
Kozubal, Justine, Heck, Tristan R., Metz, Ricardo B. |
| Zdroj: |
The Journal of Physical Chemistry - Part A; May 2019, Vol. 123 Issue: 23 p4929-4936, 8p |
| Abstrakt: |
Vibrational spectra are obtained for Cr+(NH3)1–6in the N–H stretching region (2950–3600 cm–1) using photofragment spectroscopy and complemented by calculations at the M11L/6-311++G(3df,3pd) level of theory. Because of the high bond dissociation energies of Cr+(NH3) and Cr+(NH3)2, their spectra are obtained via N2tagging; the spectrum of Cr+(NH3) is also obtained by vibrationally mediated photodissociation. The spectra all show intense peaks near 3380 cm–1due to the antisymmetric N–H stretch. Peaks due to the symmetric N–H stretch (∼3300 cm–1) are intense for n= 1–2, weak for n= 3, and not observed for n> 3. The spectrum of Cr+(NH3) and those of Cr+(NH3)(N2)2and Cr+(NH3)2(N2) show two peaks near 3200 and 3225 cm–1due to bend overtones. The spectra indicate that the coordination number of Cr+(NH3)nis 4. In the spectra of Cr+(NH3)5–6intense, broad peaks appear in the 3080–3280 cm–1region. Peaks at 3080–3180 cm–1are due to one first-shell NH3donating to a second-shell NH3; peaks at 3180–3280 cm–1are produced by two first-shell NH3donating to a second-shell NH3. The calculations indicate that the double-donor complexes are energetically favored, while single-donor complexes are entropically favored. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
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