Experimental and Theoretical Study of the Electronic States and Spectra of TeH and TeLi.
Experimental and Theoretical Study of the Electronic States and Spectra of TeH and TeLi.
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DOI：
10.1006/jmsp.2001.8301
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发表时间：
2001-04
影响因子：
1.4
通讯作者：
K. Setzer;E. H. Fink;A. B. Alekseyev;H. Liebermann;R. Buenker
中科院分区：
文献类型：
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作者：
K. Setzer;E. H. Fink;A. B. Alekseyev;H. Liebermann;R. Buenker
用傅里叶变换光谱仪在近红外光谱范围内测量了未知自由基TLi的气相发射光谱。这些发射是从一个快速流动系统中观察到的，在该系统中，Ar载气中的碲蒸气通过微波放电并在观察管中与锂蒸气混合。在8000-9000和5700-6700厘米(-1)的高光谱分辨率下测量了两个蓝色降解谱带系统，并进行了振动和旋转分析。为了帮助分析实验数据，进行了一系列相对论组态相互作用计算，得到了TELI和等价态的势能曲线以及连接它们的电偶极跃迁矩。与TIH系统一样，TELI的基态为X(2)PI(I)，但自旋-轨道分裂小得多。TELI计算表明A(2)Sigma(+)态处于强束缚状态，而在TELI计算中，类似态位于更高的约32 000 cm(-1)处，并且它是强烈预解离的。在理论分析的基础上，将观测到的TELI波段系统归属为跃迁A(2)Sigma(+)(A1/2)-->；X(1)(2)Pi(3/2)(X(1)3/2)和A(2)Sigma(+)(A1/2)-->；X(2)(2)Pi(1/2)(X(2)1/2).光谱分析得到分子常数X(1)(2)pI(3/2)：omega(E)=457.49(3)，omega(E)x(E)=2.482(9)，B(0)=0.408908(8)；X(2)(2)Pi(1/2)：T(E)=2353.44(3)，omega(E)=456.28(4)，omega(E)x(E)=2.635(8)，B(0)=0.414954(8)，p(0)=1.00637(4)；A(2)Sigma(+)：T(E)=8574.64(2)，omega(E)=437.81(3)，omega(E)x(E)=2.581(8)，B(0)=0.423903(8)，p(0)=-0.19915(2)，其中括号中的数字是参数的标准差。比较了等价态的TELI和THH体系，强调了成键性质的差异(TELI中的离子和TH中的共价)是导致这两个分子电子光谱定性差异的原因。学术出版社版权所有2001年。
Gas-phase emission spectra of the hitherto unknown free radical TeLi have been measured in the NIR range with a Fourier-transform spectrometer. The emissions were observed from a fast flow system in which tellurium vapor in argon carrier gas was passed through a microwave discharge and mixed with lithium vapor in an observation tube. Two systems of blue-degraded bands were measured at high spectral resolution in the ranges 8000-9000 and 5700-6700 cm(-1) and vibrational and rotational analyses were performed. In order to aid in the analysis of the experimental data, a series of relativistic configuration interaction calculations has been carried out to obtain potential curves for the low-lying states of TeLi and the isovalent TeH and also electric dipole transition moments connecting them. As in the TeH system, the ground state of TeLi is found to be X(2)Pi(i), but with a remarkably smaller spin-orbit splitting. The TeLi calculations indicate a strongly bound A(2)Sigma(+) state, while in TeH the analogous state is computed to lie significantly higher at approximately 32 000 cm(-1), and it is strongly predissociated. Based on the theoretical analysis, the observed TeLi band systems are assigned to the transitions A(2)Sigma(+)(A1/2)-->X(1)(2)Pi(3/2)(X(1)3/2) and A(2)Sigma(+)(A1/2)-->X(2)(2)Pi(1/2)(X(2)1/2). Analysis of the spectra has yielded the molecular constants (in cm(-1)) X(1)(2)Pi(3/2):omega(e)=457.49(3), omega(e)x(e)=2.482(9), B(0)=0.408908(8); X(2)(2)Pi(1/2): T(e)=2353.44(3), omega(e)=456.28(4), omega(e)x(e)=2.635(8), B(0)=0.414954(8), p(0)=1.00637(4); A(2)Sigma(+): T(e)=8574.64(2), omega(e)=437.81(3), omega(e)x(e)=2.581(8), B(0)=0.423903(8), p(0)=-0.19915(2), where the numbers in parentheses are the standard deviations of the parameters. Comparison of the isovalent TeLi and TeH systems emphasizes that the difference in bonding character (ionic in TeLi vs covalent in TeH) is responsible for qualitative differences in the electronic spectra of these two molecules. Copyright 2001 Academic Press.