CHEM01200604005 A. K. Pathak - Homi Bhabha National Institute

A
DACF
IR Intensity
IR Intensity
B
C
3000 3200 3400 3600 3800 4000
Photon Energy (cm -1 )
I
II
Fig. 3.4. (I) FT-DACF IR spectra of Cl •− 2 .3H 2 O at 100K. (II) Weighted average scaled IR spectra (red line)
of (A) Cl •− 2 .3H 2 O, (B) Cl •− 2 .4H 2 O and (C) Cl •− 2 .5H 2 O at BHHLYP/6-311++G(d,p) level of theory. The
black line denotes the experimental IR spectra and is reproduced from ref.24 with the permission from the
American Chemical Society. The weight factor is calculated based on Boltzmann population at 100K.
Lorentzian line shape has been applied with peak half-width of 5 cm -1 for Cl •− 2 .3H 2 O and Cl •− 2 .5H 2 O and
10 cm -1 for Cl •− 2 .4H 2 O.
IR spectra of X. nH 2 O (X= Br 2 •− and I 2 •− ) clusters are calculated at BHHLYP/6-
311++G(d,p) and X. nH 2 O (X= CO 3 •− , NO 3
−
and CO 3 2− ) clusters are calculated at
B3LYP/6-311++G(d,p) level of theory. Weighted average IR spectra based on
Boltzmann population factor is also generated for all the systems. It is observed that the
clustering makes the shifting of O-H stretching mode of water in a similar fashion for all
the halogen dimer radical anion system, X. nH 2 O (X= Cl •− 2 , Br •− 2 and I •− 2 ). The weighted
average IR spectra for X. 5H 2 O (X= CO 3 •− , NO 3
−
and CO 3 2− ) clusters is shown in Fig.
3.5 (A-C), respectively as a representative result. However, the calculated IR spectra for
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