P. N. Lebedev Physical Institute, Samara, 443011, Russia.
Phys Chem Chem Phys. 2018 Dec 5;20(47):29677-29683. doi: 10.1039/c8cp06231e.
Rate constants for singlet oxygen collision induced emission of the a1Δg-X3Σ-g transition at 1.27 μm were measured for CO2, N2, SF6, and rare gases as collisional partners. Photolysis of ozone by 266 nm laser radiation produced singlet oxygen. We performed direct measurements of pressure dependences of the 1.27 μm emission intensity for partner gases. The measured rate constants kMa-X in the units of 10-24 cm3 s-1 are as follows: CO2 - 10 ± 2; N2 - 3.2 ± 0.6; SF6 - 7 ± 1; He - 1.1 ± 0.3; Ne - 1.3 ± 0.3; Ar - 2.8 ± 0.6; Kr - 6 ± 1. The measured values of kMa-X are close to the values calculated from absorption measurements. Considering the known rate constants kMb-a for the b1Σg+-a1Δg transition in the gas phase we found that the ratio kMa-X/kMb-a was constant and independent of a collisional partner according to the "spin-orbit based" mechanism of intensity borrowing proposed by Minaev (THEOCHEM, 1989, 183, 207). However, this ratio amounted to (1.3 ± 0.2) × 10-4, which is considerably lower than the theoretically predicted value of (3-6) × 10-4.
对于 CO2、N2、SF6 和稀有气体等碰撞伙伴，测量了 1.27 μm 处 a1Δg-X3Σ-g 跃迁的单线态氧碰撞诱导发射的速率常数。通过 266nm 激光辐射光解臭氧产生单线态氧。我们对 1.27 μm 发射强度随伙伴气体压力的直接测量。以 10-24 cm3 s-1 为单位测量的测量速率常数 kMa-X 如下：CO2-10±2；N2-3.2±0.6；SF6-7±1；He-1.1±0.3；Ne-1.3±0.3；Ar-2.8±0.6；Kr-6±1。测量的 kMa-X 值接近根据 Minaev（THEOCHEM，1989，183，207）提出的基于自旋轨道的强度借用机制从气相中的 b1Σg+-a1Δg 跃迁的吸收测量计算的值。然而，该比率达到（1.3±0.2）×10-4，远低于理论预测值（3-6）×10-4。
