CHEM01200604005 A. K. Pathak - Homi Bhabha National Institute
CHEM01200604005 A. K. Pathak - Homi Bhabha National Institute
CHEM01200604005 A. K. Pathak - Homi Bhabha National Institute
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to the maximum charge transfer of the excess electron to the solvent CO 2 units in this<br />
particular cluster.<br />
In summary, degeneracy of bending mode of free solvent CO 2 unit is lost when it<br />
interacts with charged solute I •− 2 to form a molecular cluster. Two vibrational bands are<br />
observed at the bending region (~ 650 cm -1 ) of CO 2 in normal mode analysis. Both the<br />
stretching modes of CO 2 are red shifted compared to the free molecule but the bending<br />
mode is both red and blue shifted compared to the free molecule in these solvated<br />
clusters. IR spectra plot of I •− 2 nCO 2 (n=1-10) clusters show similar features. Vibrational<br />
band at the bending region of CO 2 (~ 650 cm -1 ) in Raman spectra is a characteristic<br />
feature for the formation of I •− 2 .CO 2 cluster. A weak band in the asymmetric stretching<br />
region (~ 2330 cm -1 ) of CO 2 vibration appears in the Raman spectra in these solvated<br />
clusters and the band is most intense for I •− 2 9CO 2 cluster.<br />
7.4. Conclusions<br />
Structure, energy and spectra of I •− 2 .nCO 2 clusters (n=1-10) are reported to study<br />
the process of microsolvation of the negatively charged solute, I •− 2 in carbon dioxide.<br />
Hybrid density functional (BHHLYP) is applied to study the structural aspects of the<br />
present solvated clusters with a split valence 6-311+G(d) basis function. Monte Carlo<br />
based simulated annealing procedure is also applied to find out the global minimum<br />
energy structure. Solvent stabilization and interaction energies are calculated applying<br />
MP2 as well as CCSD(T) theory. It is observed that both the solvent stabilization as well<br />
as interaction energy continuously increases with the successive addition of solvent CO 2<br />
units. It is clearly seen that the VDE values is blue-shifted with increasing cluster size<br />
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