A Study about the Optical Absorption Spectra of KCl:Hg<sup>+</sup>

Moreno, M.

doi:10.1002/pssb.2221030150

Cited by 3 publications

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“…A similar peak was observed in KC1 : Hg ÷ crystals [9] (Table I). The narrow band at 315 nm is assigned to the dimer formed by the two KBr nearby Hg + centres giving rise to Hg2+ + configuration.…”

Section: Department Of Physics Nizam College Osmania University Hysupporting

confidence: 80%

“…Moreno [9] studied and interpreted the optical absorption spectra of Hg+-doped KC1 assuming KC1 [ M X 6 ] configuration where M = Hg + replacing K +, and X = C1-. The molecular orbital (MO) theory for the complex assigns the band at 290 nm to 6s (2 $1/2) ~ NaG1 6p (2p1/2) t r a n s i t i o n in the one electron levels of Hg + .…”

Section: Department Of Physics Nizam College Osmania University Hymentioning

confidence: 99%

“…Because the optical peaks of Hg ÷ could be interpreted in terms of the MO theory of'Moreno [9], it is suggested that Hg ÷ replaces NH4 + substitutionally and forms M X 6 , (with M = N H~, X = C1 ) complex as in the isostructural K C I : H g ÷ case. Because the optical peaks of Hg ÷ could be interpreted in terms of the MO theory of'Moreno [9], it is suggested that Hg ÷ replaces NH4 + substitutionally and forms M X 6 , (with M = N H~, X = C1 ) complex as in the isostructural K C I : H g ÷ case.…”

Section: Department Of Physics Nizam College Osmania University Hymentioning

confidence: 99%

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Optical peaks of mercury centres in NH4Cl

et al. 1987

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The ammonium halide materials, which find applications in optical modulators in the form of single crystals, have been the subject of a great variety of investigations because of their interesting transport and optical properties together with their structure modifications in different temperature intervals [1][2][3][4][5][6][7]. In particular, the optical properties of these materials are very much influenced by the defects introduced in the form of impurities and also by the defects induced by high-energy radiation.The optical absorption spectra of NH4C1 doped with transition metal ions have been studied previously [5 7]. However, the study of optical spectra of NH4CI doped with heavy ions such as Hg 2+ has not been undertaken. In addition, there are very few reports on the study of radiation damage of pure or doped NH4C1 crystals. In this letter the analysis of optical absorption spectra of NH4C1 doped with HgC12, before and after X-irradiation, are presented.The pure NH4C1 crystals were grown by slow evaporation of the saturated aqueous solution containing AR grade NH4C1 and 30% urea at room temperature. The doped crystals were grown by a similar method with the addition of HgC12 (2% by weight) to the original solution.The pure and doped crystals were irradiated with X-rays from a radon House unit operating at 30kV and 10mA. The optical absorption spectra of the crystals were recorded on a Shimadzu UV visible spectrophotometer.The optical absorption spectra of the undoped NHaC1 crystals before irradiation and after 3h X-irradiation are shown in Fig. 1 a and b, respectively. The curve a suggests that the undoped crystal is transparent in the ultraviolet (UV) and visible region. Because curve b is almost identical to curve a, the radiation appears to cause no damage to either NH~ or C1 ions in the lattice and no new centres which absorb in the UV or visible region at RT are produced.The spectrum of NH4C1 doped with mercury is shown in Fig. 2a. The optical peaks appear only in the UV and near-UV region with the region beyond 450 nm left optically free. The broad band at 350 nm is attributed to Hg 2+ centres as it has been uniformly observed in other lattices (Table I). It is known that the mercuric (Hg 2+) and mercurous (Hg ÷) ions are equally stable in the solid state [8]: it is highly probable that Hg ÷ formed from HgCI2 in solution enters the NHaC1 material together with Hg 2÷ at the time of crystal growth. Further, it is known [8] that Hg ÷ )

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Section: Department Of Physics Nizam College Osmania University Hysupporting

confidence: 80%

Section: Department Of Physics Nizam College Osmania University Hymentioning

confidence: 99%