Liu Jinjun, Chen Ming-Wei, Melnik Dmitry, Miller Terry A, Endo Yasuki, Hirota Eizi
Department of Chemistry, Laser Spectroscopy Facility, The Ohio State University, Columbus, Ohio 43210, USA.
J Chem Phys. 2009 Feb 21;130(7):074303. doi: 10.1063/1.3072105.
Rotationally resolved laser-induced fluorescence (LIF) and stimulated emission pumping (SEP) A (2)A(1)-X (2)E spectra of the perdeuteromethoxy radical (CD(3)O) have been observed. These data directly connect the two spin-orbit components (E(1/2) and E(3/2)) of the ground electronic state with high precision. Molecular constants for both electronic states are determined in a global fitting that involves LIF, SEP, and pure rotational spectra in the microwave region. For the microwave transitions, the resolved hyperfine structure is analyzed providing molecular parameters characterizing it and hyperfine-free transitions for the global fitting. A complete "experimental" geometry for the methoxy radical at the C(3v) conical intersection is determined from the rotational constants of its isotopologs. The experimental isotopic dependence of other parameters in the effective Hamiltonians is compared to the theoretically expected variation. These comparisons allow considerable insight into the physical significance of a number of parameters in the effective Hamiltonian. In particular, experimental evidence is found for a previously predicted vibrational correction to the A rotational constant of a Jahn-Teller active molecule.
已观测到全氘代甲氧基自由基（CD₃O）的转动分辨激光诱导荧光（LIF）和受激发射泵浦（SEP）A (²)A₁ - X (²)E光谱。这些数据高精度地直接关联了基电子态的两个自旋 - 轨道分量（E₁/₂和E₃/₂）。通过全局拟合确定了两个电子态的分子常数，该拟合涉及LIF、SEP以及微波区域的纯转动光谱。对于微波跃迁，分析了分辨出的超精细结构，提供了表征它的分子参数以及用于全局拟合的无超精细跃迁。根据其同位素变体的转动常数确定了甲氧基自由基在C₃v锥形交叉点处的完整“实验”几何结构。将有效哈密顿量中其他参数的实验同位素依赖性与理论预期变化进行了比较。这些比较有助于深入了解有效哈密顿量中许多参数的物理意义。特别是，发现了关于先前预测的对Jahn - Teller活性分子A转动常数的振动校正的实验证据。
