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BeC是一个具有丰富低激发电子态的分子, 本文基于动态权重完全活性空间自冾场方法获得的参考波函数, 采用多参考组态相互作用方法对BeC分子进行高精度的从头计算, 获得了BeC分子
$ {{\rm{X}}^3} {{\text{Σ}} ^ - } $ ,${\rm{A}}^3 {\text{Π}}$ ,$ {{\rm{b}}^1} {{\text{Δ}} } $ ,${{\rm{c}}^1} {\text{Π}}$ 和$ {{\rm{d}}^1}{{\text{Σ}} ^ + } $ 共5个电子态的势能曲线. 为了获得精确的光谱结果, 在计算中考虑了标量相对论效应修正, 并把相互作用能外推至完全基组极限. 在此基础上获得了这些态的光谱常数和偶极距, 以及一些允许跃迁的跃迁偶极距、弗兰克-康登因子和辐射寿命. 最后, 通过扩展的Rydberg函数拟合获得了基态势能曲线精确的解析表达式.Diatomic molecule BeC has a complex electronic structure with a large number of low-lying excited states that are all strongly bound electronic states. Thus, the BeC molecule has the abundant spectral information. In this work, the potential energy curves and wavefunctions of$ {{\rm{X}}^3} {{\text{Σ}} ^ - } $ ,${\rm{A}}^3 {\text{Π}}$ ,$ {{\rm{b}}^1} {{\text{Δ}} } $ ,${{\rm{c}}^1} {\text{Π}}$ and$ {{\rm{d}}^1}{{\text{Σ}} ^ + } $ states of the BeC molecule are calculated by using the internally contracted multi-reference configuration interaction (MRCI) approach, which is based on the use of a dynamically weighted complete active space self-consistent field (DW-CASSCF) procedure. To improve the reliability and accuracy of calculation, the scalar relativistic corrections and the extrapolation of potential energy to the complete basis set limit are taken into account. On the basis of the calculated potential energy curves and wavefunctions, the spectroscopic constants ( T e, R e,${\omega _{\rm{e}}}$ ,${\omega _{\rm{e}}}{x_{\rm{e}}}$ ,${\omega _{\rm{e}}}{y_{\rm{e}}}$ , B e,${\alpha _{\rm{e}}}$ , and D e) and permanent dipole moments of those states are determined, the results of which are in good agreement with the existing available experimental and theoretical values. The obtained permanent dipole moments indicate that the electrons transfer from Be to C and the polarity for molecule is$ {\rm{B}}{{\rm{e}}^{{\text{δ}} + }}{{\rm{C}}^{{\text{δ}} - }}$ . The transition properties of the spin-allowed${\rm{A}}^3 {\text{Π}}$ −$ {{\rm{X}}^3} {{\text{Σ}} ^ - } $ ,${{\rm{c}}^1} {\text{Π}}$ −$ {{\rm{b}}^1} {{\text{Δ}} } $ ,${{\rm{c}}^1} {\text{Π}}$ −$ {{\rm{d}}^1}{{\text{Σ}} ^ + } $ transitions are predicted, including the transition dipole moments, Franck-Condon factors, and radiative lifetimes. The radiative lifetimes for the${\rm{A}}^3 {\text{Π}}$ −$ {{\rm{X}}^3} {{\text{Σ}} ^ - } $ transitions are predicated to be at a$ {{\text{µ}}\rm{ s}}$ level, and the good agreement with previous theoretical values is found. Radiative lifetimes for${{\rm{c}}^1} {\text{Π}}$ −$ {{\rm{b}}^1} {{\text{Δ}} } $ and${{\rm{c}}^1} {\text{Π}}$ −$ {{\rm{d}}^1}{{\text{Σ}} ^ + } $ transitions are also evaluated at the levels of$ {{\text{µ}}\rm{ s}}$ and ms, respectively. The PEC for the ground state is fitted into accurate analytical potential energy functions by using the extended-Rydberg potential function.[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] [20] [21] [22] [23] [24] [25] [26] [27] [28] [29] [30] [31] [32] [33] [34] [35] [36] [37] [38] -
原子态 $ {\text{Λ}}{\text{-}}{\rm S}$态 相对能量/cm–1 本文 (无Q) 本文 (+Q) 实验值[34] Be(1Sg)+C(3Pg) $ {{\rm{X}}^3} {{\text{Σ}} ^ - } $, ${\rm{A}}^3 {\text{Π}}$ 0 0 Be(1Sg)+C(1Dg) $ {{\rm{b}}^1} {{\text{Δ}} } $, ${{\rm{c}}^1} {\text{Π}}$, $ {{\rm{d}}^1}{{\text{Σ}} ^ + } $ 10124.12 10169.70 10192.66 Be(1Sg)+C(1Sg) ${2^1}{{\text{Σ}} ^ + } $ 21679.58 21581.62 21648.03 
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Te/cm–1 Re/nm ${\omega _{\rm{e}}}$/cm–1 $ {\omega _{\rm{e}}}{x_{\rm{e}}} $/cm–1 102${\omega _{\rm{e}}}$уe/cm–1 Be/cm–1 $ {10^3}{\alpha _{\rm{e}}}$/cm–1 De/eV ${{{\rm{X}}^3}{\text{Σ}}^- } $ 0 0.1673 918.08 7.350 17.87 1.1783 15.644 2.1873 Cal. [6] 0 0.1661 937.9 9.6 — 1.19 — — Cal. [7] 0 0.1693 905 — — — — 2.04 Cal. [8] 0 0.1667 951 8.42 — 1.183 — 2.39 Cal. [10] 0 0.1683 925 11.25 — — — 2.14 Cal. [19] 0 0.1680 — — — — — 2.04 ${{\rm{A}}^3}{\text{Π}}$ 8916.35 0.1771 772.74 8.692 199.89 1.0518 28.367 1.0777 Cal. [7] 9033.41 0.1799 — — — — — 0.92 Cal. [8] 9466 0.1756 764 14.69 — 1.0752 — 1.16 Cal. [10] 8961 0.1791 874 26.26 — — — 1.03 $ {{\rm{b}}^1}{\text{Δ}} $ 7823.39 0.1675 933.50 8.301 7.56 1.1714 16.700 2.4408 Cal. [7] 8872.10 0.1693 904 — — — — 2.27 Cal. [8] 8732 0.1668 956 7.6 — 1.1757 — 2.63 $ {{\rm{c}}^1}{\text{Π}} $ 10909.21 0.1760 834.80 7.138 9.20 1.0551 14.365 2.0933 Cal. [7] 11291.76 0.1778 818 — — — — 1.97 Cal. [8] 11618 0.1758 847 6.94 — 1.0612 — 2.24 $ {{\rm{d}}^1}{{\text{Σ}} ^ + } $ 12139.14 0.16698 936.21 17.553 126.98 1.1764 16.000 1.9060 Cal. [7] 12582.24 0.1693 905 — — — — 1.81 Cal. [8] 13579 0.167 955 7.3 — 1.1732 — 2.02 注: Cal. 为理论计算值. 下载:
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$\nu '$—$ \nu ''$ FC $\nu '$—$ \nu ''$ FC $\nu '$—$ \nu ''$ FC $\nu '$—$ \nu ''$ FC $\nu '$—$ \nu ''$ FC $\nu '$— $ \nu ''$ FC ${\rm{A}}^3 {\text{Π}}$—${\rm{X}}^3 {\text{Σ}}^-$ 0—0 0.5439 0—1 0.3653 1—0 0.3049 1—2 0.4143 1—3 0.1670 2—0 0.1080 2—1 0.2660 2—3 0.3601 2—4 0.2276 3—2 0.1654 3—4 0.2908 3—5 0.2691 4—2 0.1763 4—5 0.2255 4—6 0.2993 5—3 0.1561 5—6 0.1639 5—7 0.3216 6—3 0.1070 6—4 0.1273 6—6 0.1339 6—7 0.1052 6—8 0.3348 6—9 0.1183 7—4 0.1095 7—5 0.1000 7—7 0.1618 7—9 0.3342 7—10 0.1531 ${{\rm{c}}^1}{\text{Π}}$ —${{\rm{b}}^1}{\text{Δ}}$ 0—0 0.6237 0—1 0.3153 1—0 0.2701 1—1 0.1740 1—2 0.3999 1—3 0.1368 2—1 0.2689 2—3 0.3470 2—4 0.2322 3—1 0.1518 3—2 0.1803 3—4 0.2122 3—5 0.2964 4—2 0.1894 4—4 0.1027 4—5 0.1045 4—6 0.3042 4—7 0.1238 5—3 0.1634 5—5 0.1435 5—7 0.3138 6—3 0.1236 6—4 0.1268 6—6 0.1567 6—8 0.2968 7—4 0.1289 7—7 0.1495 7—9 0.2690 8—5 0.1219 8—8 0.1212 8—10 0.2380 9—11 0.2025 10—12 0.1699 ${{\rm{d}}^1}{\text{Σ}}$—${{\rm{c}}^1}{\text{Π}}$ 0—0 0.6164 0—1 0.2717 1—0 0.3232 1—1 0.1693 1—2 0.2617 2—1 0.4016 2—3 0.1699 2—4 0.1850 3—1 0.3901 3—2 0.3513 3—5 0.1510 4—2 0.2362 4—3 0.2156 4—4 0.1073 4—6 0.1068 5—3 0.3014 5—4 0.1011 5—5 0.1501 6—4 0.3109 6—6 0.1613 7—4 0.1292 7—5 0.3175 7—7 0.1442 8—5 0.1801 8—6 0.2945 8—8 0.1054 9—6 0.2192 9—7 0.2612 10—7 0.2563 10—8 0.2265 下载:
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跃迁 辐射寿命$/{{\text{μ}}{\rm{ s}}}$ $\nu '$ = 0 $\nu '$ = 1 $\nu '$ = 2 $\nu '$ = 3 $\nu '$ = 4 $\nu '$ = 5 $\nu '$ = 6 $\nu '$ = 7 ${\rm{A}}^3 {\text{Π}}$—${{\rm{X}}^3}{{\text{Σ}} ^ - }$ 14.66 14.64 14.46 13.82 12.99 12.16 11.65 11.31 Cal.[10] 14.0 14.5 15.6 ${{\rm{c}}^1} {\text{Π}}$—$ {{\rm{b}}^1} {{\text{Δ}} } $ 191.10 166.59 161.38 159.48 151.88 176.09 197.32 239.85 ${{\rm{c}}^1} {\text{Π}}$—$ {{\rm{d}}^1}{{\text{Σ}} ^ + } $ 2730.00 1010.00 630.00 460.00 380.00 330 280.00 230.00 下载:
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参数 C1 C2 C3 C4 C5 参数值 4.584720688 6.825173375 4.979780662 2.012372055 1.900852427 参数 C6 C7 C8 C9 C10 参数值 –5.415648763 –6.033517345 12.82526525 –6.086434893 0.939009741 下载:
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[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] [20] [21] [22] [23] [24] [25] [26] [27] [28] [29] [30] [31] [32] [33] [34] [35] [36] [37] [38]
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