Hartree–Fock calculation of BaF2:La systems

Sobolev, A. B.; Kuznetsov, A. Yu.; Andriessen, J.; Eijk, C.W.E. van

doi:10.1016/s0168-9002(02)00738-6

Cited by 6 publications

(2 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is known that the C 3v centres are predominant in BaF 2 . This follows from ionic thermocurrent measurements [12] and from theoretical calculations [13,14]. The splitting of 4f t 2g transitions by interstitial C 3v fluorine is minimal due to the long distance between them.…”

Section: Discussionmentioning

confidence: 91%

Cubic and tetragonal Ce³⁺ions in strontium fluoride

Раджабов

Kurobori

2004

J. Phys.: Condens. Matter

View full text Add to dashboard Cite

Optical absorption spectra in the vacuum ultraviolet region and high resolution emission and absorption spectra in the ultraviolet region for cubic and tetragonal Ce3+ centres in SrF2 crystals were measured. Cubic centres are characterized by a 33 250 cm−1 zero-phonon line and a sharp phonon line spaced from the zero-phonon line by 410 cm−1. The decay times of cubic and tetragonal centre luminescences are 32 ns. Comparison of cubic and tetragonal spectra allows us to establish the influence of charge compensating interstitial fluorine ions on f and d levels of Ce3+ ions. Non-empirical Hartree–Fock calculations for Ce states in molecular clusters of alkaline-earth fluorides were performed. To make the calculated transitions coincide with the experimental ones one needs to take into account a shift of Ce3+ and interstitial F− towards each other by 10% of the initial distance.

show abstract

Section: Discussionmentioning

confidence: 91%

Cubic and tetragonal Ce³⁺ions in strontium fluoride

Раджабов

Kurobori

2004

J. Phys.: Condens. Matter

View full text Add to dashboard Cite

show abstract

“…There is experimental evidence that interstitial fluorine states in BaF 2 :LaF 3 lie above the top of the valence band [9]. According to quantum chemical calculations for BaF 2 :LaF 3 crystals, interstitial fluorine states appear above the top of the valence band [16,17] and La states appear below the bottom of the conduction band [16]. Therefore, during illumination into the impurity excitation band of La-doped BaF 2 crystal, electrons transfer from interstitial fluorine states to La states.…”

Section: Discussionmentioning

confidence: 99%

Configurations of excitons in BaF2$ndash$LaF3 crystals

Раджабов¹,

Nepomnyashikh²,

Egranov³

2002

J. Phys.: Condens. Matter

View full text Add to dashboard Cite

Exciton luminescence was investigated in La-doped BaF 2 crystals. Two luminescence bands at 4.26 and 3.82 eV related to excitons have been observed. The excitation spectrum of the 4.26 eV band of BaF 2 -LaF 3 was similar to that of the exciton emission band of pure BaF 2 crystals. The excitation spectrum of the 3.82 eV band shows a new band within the 8-9 eV region. The band becomes most prominent for BaF 2 -3 wt% LaF 3 and has a maximum at 8.7 eV at 290 K.The decay time for the 4.26 eV emission band of BaF 2 -3% LaF 3 considerably increased with decreasing temperature like the exciton decay time for pure BaF 2 , where the decay time of unperturbed excitons grows to 121 µs at 17 K. In contrast to this, the decay time of the 3.82 eV band increases from 4.1 µs at 290 K to 6.2 µs at 15 K. The significant reduction of the triplet-singlet decay time can be associated with strong interaction of excited electrons with lanthanum ions.It was concluded that the 4.26 eV emission band is associated with weakly perturbed excitons, while the 3.82 eV band is associated with strongly perturbed excitons. The possible spatial configurations of excitons are discussed.

show abstract