CHEM01200604004 Shri Sanyasinaidu Boddu - Homi Bhabha ...

any Eu 3+ ions is characterised by sharp peaks at 1016, 947, 658, 526, 474, and 385 cm -1
(Fig.23A) along with a broad peak in the region 3670-2640 cm -1 (Fig.23 (B)). As is evident
from Fig.23 (A) the peaks at 385 and 526 cm -1 disappear with Eu 3+ incorporation, while the
peaks at ~ 474, 658, 947 and 1016 cm -1 are broadened. Furthermore, new modes starts
appearing at 1490 and 1635 cm -1 , which are absent in pure GaOOH sample. Similar changes
are also observed in the Raman spectra (Fig.23 (C)). The signal to noise ratio of Raman
spectrum degraded significantly when Eu 3+ content increased beyond 1 at %. The Raman
spectrum of sample without Eu 3+ incorporation shows well-defined peaks at ~ 276, 433, 525,
612 and 696 cm -1 . With Eu 3+ incorporation, width of the Raman peaks at ~525 cm -1 and 612
cm -1 increase, due to the development of additional shoulder peaks at ~ 550 and ~ 650 cm -1
and is attributed to GaOOH lattice distortions. A Summary of peaks observed with different
samples with possible assignments, together with that observed in Ga(OH) 3 is given in Table
2. As the peaks are significantly overlapping, de-convolution of individual peaks from the IR
patterns could not be performed for estimating the line width. Even though there is
broadening of peaks with increase in Eu 3+ content, the peak positions corresponding to
different vibrational modes in these samples remained same within experimental errors.
Transmittence
526
385
474
658
947
1016
1383
1490
1635
(f)
(e)
(d)
(c)
(b)
(a)
300 600 900 1200 1500 1800
Wavenumber (cm -1 )
(A)
Transmittence
2975
3250
3400
(f)
(e)
(d)
(c)
(b)
(a)
2000 2500 3000 3500 4000
Wavenumber (cm -1 )
(B)
Normalized Raman intesity
(C)
276
Plasma line
612
525
433
0.75 at % Eu
1.0 at % Eu
Undoped
696
200 400 600 800 1000
Raman shift (cm -1 )
Fig.23. FT-IR patterns (A and B) of GaOOH sample prepared in presence of (a) 0 at % (b)
0.5 at % (c) 0.75 at % (d) 1 at % (e) 2 at % of Eu 3+ ions and (f) amorphous Ga(OH) 3 .
The Raman spectrum from the representative samples are shown in Fig.23 (C).
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