Abstract:one energy. It is not necessary that dg r&g Bk J J s j with the integral performed over a surface of constant energy, be positive for some such surface. The necessary condition for negative resistance in the i direction only demands that Bg/dE along some line in the i direction be positive. In Ge and Si with warped heavy-hole bands, the necessary reversal may only correspond toIn this Letter we describe direct observations of bimolecular band-to-band transitions at rectifying junctions in single crystals of ga… Show more
“…of the order of 100 per degree ν of K-suppression (ν = |∆K − L|) where τ (W.u.) is the Weisskopf estimate for the lifetime τ of an EL or ML electromagnetic transition [24].…”
Section: Stellar Transition Rates Between Low-k and High-k Statesmentioning
confidence: 99%
“…The cross section for 24 Na irradiation is about a factor of 500 higher [10]. The 60 Co result of [15] has been translated to an integrated cross section of I σ ≈ 6 − 7 eV fm 2 under the assumption of an IS located at 1 MeV [10,17].…”
The s-process branching at mass number A = 176 depends on the coupling between the high-K ground state and a low-lying low-K isomer in 176 Lu. This coupling is based on electromagnetic transitions via intermediate states at higher energies. The properties of the lowest experimentally confirmed intermediate state at 839 keV are reviewed, and the transition rate between low-K and high-K states under stellar conditions is calculated on the basis of new experimental data for the 839 keV state. Properties of further candidates for intermediate states are briefly analyzed. It is found that the coupling between the high-K ground state and the low-K isomer in 176 Lu is at least one order of magnitude stronger than previously assumed leading to crucial consequences for the interpretation of the 176 Lu/ 176 Hf pair as an s-process thermometer.
“…of the order of 100 per degree ν of K-suppression (ν = |∆K − L|) where τ (W.u.) is the Weisskopf estimate for the lifetime τ of an EL or ML electromagnetic transition [24].…”
Section: Stellar Transition Rates Between Low-k and High-k Statesmentioning
confidence: 99%
“…The cross section for 24 Na irradiation is about a factor of 500 higher [10]. The 60 Co result of [15] has been translated to an integrated cross section of I σ ≈ 6 − 7 eV fm 2 under the assumption of an IS located at 1 MeV [10,17].…”
The s-process branching at mass number A = 176 depends on the coupling between the high-K ground state and a low-lying low-K isomer in 176 Lu. This coupling is based on electromagnetic transitions via intermediate states at higher energies. The properties of the lowest experimentally confirmed intermediate state at 839 keV are reviewed, and the transition rate between low-K and high-K states under stellar conditions is calculated on the basis of new experimental data for the 839 keV state. Properties of further candidates for intermediate states are briefly analyzed. It is found that the coupling between the high-K ground state and the low-K isomer in 176 Lu is at least one order of magnitude stronger than previously assumed leading to crucial consequences for the interpretation of the 176 Lu/ 176 Hf pair as an s-process thermometer.
“…Absorption measurements at room temperature were also carried out by Loebner and Poor [295]. They found that their results for values of the absorption coefficient, a, between 10 and 150 cm-l can be fitted t o the MacfarlaneRoberts expression.…”
“…Following Loebner and Poor Jr. (Ref. [16]) the green band was attributed to recombination of a free electron with a free hole (although a more detailed analysis later (Ref. [19]) showed this to be unlikely).…”
Section: The Growing Interest In Gapmentioning
confidence: 97%
“…One year later, Loebner and Poor (Ref. [16]) found two emission bands in GaP depending on the direction of the current. All these observations were important steps, but the experimental conditions were not sufficiently well defined for the mechanism of electroluminescence to be established.…”
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