Vibrational properties and infrared spectra ofAlxGa1−xAs systems. II. Order and disorder features in superlattice configuration

1991 ◽  
Vol 43 (18) ◽  
pp. 14457-14464 ◽  
Author(s):  
M. Bernasconi ◽  
L. Colombo ◽  
L. Miglio
RSC Advances ◽  
2018 ◽  
Vol 8 (59) ◽  
pp. 33985-33992
Author(s):  
Ben Xu ◽  
Anna Hirsch ◽  
Leeor Kronik ◽  
Kristin M. Poduska

Isotopic enrichment in calcite, even at relatively low levels, can produce surprising changes to infrared spectra.


2015 ◽  
Vol 775 ◽  
pp. 191-196
Author(s):  
Xiao Wei Lei ◽  
Yong Song ◽  
Kuo Yang ◽  
Hui Zhao

Using first principles approach, we present the structural, vibrational and dielectric properties of α-SiO2. The calculations have been carried out within the density functional perturbation theory and linear response formalism using the norm-concerving pseudopotentials and a plane wave basis. All the vibrational modes identified are in good agreement with experiment. The calculated infrared spectra are also in good agreement with available experimental results both for the positions and the intensities of the main peaks. We find that the modes Eu7 and A2u4 splits in two respectively at high hydrostaticpressures. Then we calculate the infrared spectra under high pressure of different orientations. The vibrational modes in different phase transitions are reported and discussed respectively.


1973 ◽  
Vol 39 (303) ◽  
pp. 282-288 ◽  
Author(s):  
V. C. Farmer ◽  
B. Velde

SummaryComparison of the infrared spectra (4000-50 cm−1) of natural and synthetic samples of margarite, beryllian margaritc, ephesite, and clintonite indicates that the tetrahedral layers of margarite and ephcsite, containing Si and Al in equal atomic proportions, are ordered as the spectra are sharp and show no Al-O-Al vibrations. Clintonite of this tctrahedral composition is disordered. The hydroxyl-stretching frequencies are affected by ionic substitutions in both the octahedral and tetrahedral layers. The spectra permit the distinction of the different species of brittle mica. They also indicate the presence of beryllium in margarite, and allow an estimate of the tetrahedral composition of clintonites.


1990 ◽  
Vol 45 (8) ◽  
pp. 1133-1135 ◽  
Author(s):  
G. E. Narda ◽  
J. C. Pedregosa ◽  
S. B. Etcheverry ◽  
E. J. Baran

The infrared spectra of a series of cadmium substituted calcium hydroxylapatites of the type Ca10-xCdx(PO4)6(OH)2, were investigated in order to obtain insight on the effect of the Cd(II) ion on the vibrational properties of the PO43- and OH- groups. The effect of the substitutional process on the strength of the P–O bonds was also checked by Raman Spectroscopy and an analysis of the behaviour of the deuterated Ca5Cd5(PO4)6(OD)2 phase was undertaken. The strength of the P–O bonds shows a linear dependence on the Cd(II) content, whereas the OH-vibrational modes present a more complex behaviour.


1998 ◽  
Vol 77 (2) ◽  
pp. 333-340 ◽  
Author(s):  
A. Fontana, F. Rossi, G. Carini, G. D'

1981 ◽  
Vol 78 ◽  
pp. 927-932 ◽  
Author(s):  
F.J.C.M. Toolenaar ◽  
G.J. van der Poort ◽  
F. Stoop ◽  
V. Ponec

2000 ◽  
Vol 10 (PR7) ◽  
pp. Pr7-211-Pr7-214 ◽  
Author(s):  
V. Venuti ◽  
V. Crupi ◽  
S. Magazù ◽  
D. Majolino ◽  
P. Migliardo ◽  
...  

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