BeAl6O10晶体中的Cr^3＋发光中心

铬激活的BeA1_6O_(10)(BHA)晶体中Cr~(3+)离子形成多种发光中心,给出复杂的发光.发光谱中包含着荧光寿命为几十微秒至几毫秒不同的光谱成分,本文用Chrono光谱法分离子这些重迭的成分,辩认出三种铬中心——两种强场中心,Cr(Ⅰ)和Cr(Ⅱ),一种低场中心,Cr(Ⅲ).并且给出了它们占据的格位.一个单胞里可能的铬格位共有40个.其中,24个畸变了的八面体格位属于Cr(I)型中心;8个畸变较小近乎正八面体的格位属于Cr(Ⅱ)型中心;另外8个格位具有次近邻微扰结构,属于Cr(Ⅲ)型中心.Cr(Ⅲ)给出宽带发射.

Chromium center in BeAl_6O_(10):Cr crystal

Cr3+ ions in the BeAI6O10 (BHA) crystal give complicated luminescenoe spectrum with different fluorescence lifetimes from several miliseconds to several ten miorosceco-nds. "Null point phases" of these components measured by using chrono-speotroscopio technique indicate that the spectrum is due to two high-field single Cr3+-centers, Cr (Ⅰ), Cr (Ⅱ), and a low-field single Cr3+-center, Cr (Ⅲ). The crystal structure shows that, in an unit cell the possible chromium sites are 24 Cr (Ⅰ) with six distortion maners and 8 Cr(II), responsible for the main line emission, and 8 Cr(III) with a particular structure responsible for the broad band emission. At 77 K, some lens have been identified as the transitions of Cr(I), Cr(II) and Cr-pairs of the I-I and I-II types.