Fermi resonances and local modes in stibine, SbH3: A Fourier interferometric and laser photoacoustic study of the overtone spectrum

1996 ◽  
Vol 104 (2) ◽  
pp. 488-498 ◽  
Author(s):  
Juha Lummila ◽  
Tuomas Lukka ◽  
Lauri Halonen ◽  
Hans Bürger ◽  
Oliver Polanz
Keyword(s):  
1995 ◽  
Vol 102 (13) ◽  
pp. 5200-5206 ◽  
Author(s):  
Tuomas Lukka ◽  
Esa Kauppi ◽  
Lauri Halonen
Keyword(s):  

The infra-red absorption spectrum of silicon doped with high densities of boron and phosphorus has been measured from 1 to 60 μm and at temperatures between 5 and 290 °K in order to observe the local and band mode vibrational absorption activated by these impurities. The major experimental problem, that of achieving a high degree of electrical compensation to eliminate free carrier absorption, was solved by using fast electron bombardment to introduce a controllable number of trapping centres. A series of experiments was conducted to eliminate the effects of these centres from the spectrum of the chemical impurities. The characteristic spectra of the substitutional boron and phosphorus have been analysed in detail in terms of the theory of Dawber & Elliott. For local modes activated by boron isotopes close agreement with theory has been found in number of lines, strength and frequency. From the latter it is estimated that the local force constants are weakened by less than 10 % on substituting boron for silicon in the lattice. Second harmonic lines are observed at a frequency 0.25 % less than twice that of the fundamentals. The band modes exhibit a striking in-band resonance at 0.0546 eV which was not theoretically predicted. This is attributed to phosphorus and analysis shows that the theory can give such a resonance but not with parameters associated with substitutional phosphorus and unchanged force constants. Most of the remaining features in the band modes can be interpreted satisfactorily in terms of substitutional boron but this requires some modification to published data on the density of states for pure silicon. Critical points for TO( L ), TO( X ) and LA( L ) phonons are clearly identified in the spectra.


2007 ◽  
Vol 34 ◽  
pp. 411-420
Author(s):  
Ben Knighton

If there is to be a “great Karamoja debate”, then it is necessary to keep in focus the leading issues, with the constraints of historiographical and methodological concerns. Since 1990 publications on the Karamojong have in general taken the line expressed in Mirzeler and Young's abstract: “The transformation of local modes of conflict by large-scale infusion of the AK-47 has had far-reaching effects …”. Against this trend I cite the French critic, Alphonse Karr (1808-1890), “Plus ça change, plus c'est la même chose”. My perversity is sustained by studying the Karamojong over 23½ years, living there 1984-86, and returning for fieldwork across Karamoja in 1998, 2000, 2002, and 2005. Taking copies of my monograph to deposit for Karamojong literati to read, the dominant impression was that mobile telephones notwithstanding, this was the same Karamoja. I will not have the last word, but history will.The issue in Mirzeler's paper above is that “Pastoral Politics” has been mis-represented. Of course any part of an article cannot fully represent the whole, but my book cites Mirzeler no less than 49 times, often giving multiple page references. There is therefore no attempt at disguise or misappropriation: readers are invited and enabled to see for themselves. Where I have fallen down is in five sentences in one chapter, which Allen enjoys for its rare antipathy, where I have inverted commas in manifestly the wrong places. Sadly this is merely where my incompetence got the better of my conscientiousness. These five sentences were my précis, which I knew contained phrases it would have been appropriate to quote, so I marked them with inverted commas with the full intention of checking with the original article. Since I did not have it in my study, my intention was never executed, so now Mirzeler has his reward and I a lifetime's chagrin.


2007 ◽  
Vol 127 (23) ◽  
pp. 239901
Author(s):  
Paul M. Donaldson ◽  
Rui Guo ◽  
Frederic Fournier ◽  
Elizabeth M. Gardner ◽  
Laura M. C. Barter ◽  
...  

2001 ◽  
Vol 64 (14) ◽  
Author(s):  
Jon-Paul R. Wells ◽  
Ian V. Bradley ◽  
Glynn D. Jones ◽  
Carl R. Pidgeon

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