Several experimental groups have measured the rovibrational transitions of B⁴Σ^– – X⁴Σ^–, 2⁴Π – X⁴Σ^–, B⁴Σ^– – A⁴Π, and d²Σ⁺ – a²Π systems of diatomic boron carbide. However, no transition properties between any electronic states of this molecule have been calculated. This work studied the transition dipole moments between the X⁴Σ^–, A⁴Π, B⁴Σ^–, 1⁴Δ, 1⁴Σ⁺, and 2⁴Π states, between the a²Π, b²Σ^–, c²Δ, and d²Σ⁺ states, and from the a²Π_3/2 and a²Π_1/2 states to the X⁴Σ^–_3/2 and X⁴Σ^–_1/2 states. The radiative lifetimes are on the order of 10^–2 – 10^–4 s for the 1⁴Σ⁺ state, 10^–3 – 10^–4 s for the A⁴Π state, 10^–4 s for the 1⁴Δ state, 10^–4 – 10^–5 s for the c²Δ state, 10^–5 s for the b²Σ^– and d²Σ⁺ states, and 10^–7 s for the B⁴Σ^– and 2⁴Π states. The B⁴Σ^– – X⁴Σ^–, 2⁴Π – X⁴Σ^–, 2⁴Π – A⁴Π, and 2⁴Π – B⁴Σ^– transitions are strong. The transitions from the a²Π_1/2 and a²Π_3/2 states to the X⁴Σ^–_1/2 and X⁴Σ^–_3/2 states are weak. The emissions originating from the a²Π_1/2 and a²Π_3/2 states at higher vibrational levels are easier to measure than those at lower levels. The radiative lifetimes are approximately 10⁰ – 10³ and 10⁰ – 10² s for the a²Π_1/2 and a²Π_3/2 states, respectively. The band origins, Franck–Condon factors, and Einstein A coefficients of all dipole–allowed transitions were calculated. The distribution of radiative lifetime varying with rotational angular quantum number was investigated for the A⁴Π, B⁴Σ^–, 2⁴Π, b²Σ^–, and d²Σ⁺ states. The transition properties reported in this work can provide useful guidelines for future experimental and theoretical studies.

几个实验组已经测量B的振转跃迁⁴ Σ ^- - X ⁴ Σ ^-，2 ⁴ Π - X ⁴ Σ ^-，B ⁴ Σ ^- -甲⁴ Π，和d ² Σ ⁺ -一个^2个Π系统双原子的硼碳化物。然而，尚未计算出该分子的任何电子状态之间的过渡性质。这项工作研究了X之间的跃迁偶极矩⁴ Σ ^-，A ⁴ Π，B ⁴ Σ ^-，1 ⁴ Δ，1⁴ Σ ⁺，和2种^4种Π状态，所述一个之间² Π，B ² Σ ^-，C ² Δ，和d ^2个Σ ⁺状态，并且从一个² Π _3/2和^2个Π _1/2状态以的X ⁴ Σ ^- _3/2和X ⁴ Σ ^- _1/2的状态。的辐射寿命是10个量级^-2 - 10 ^-4 S为1 ⁴ Σ ⁺状态，10 ^-3 - 10 ^-4S对于在A ⁴ Π状态，10 ^-4 S对于1个⁴ Δ状态，10 ^-4 - 10 ^-5 S对于与c ² Δ状态，10 ^-5 S对于在B ² Σ ^-和d ^2个Σ ⁺状态和10个^-7 S为乙⁴ Σ ^-和2个⁴ Π状态。在B ⁴ Σ ^- - X ⁴ Σ ^-，2 ⁴ Π - X ⁴ Σ ^-，2 ⁴ Π -甲⁴ Π，和2 ⁴Π - B ⁴ Σ ^-跃迁都很强。从一个过渡² Π _1/2和^2个Π _3/2状态到X ⁴ Σ ^- _1/2和X ⁴ Σ ^- _3/2状态是弱。排放从一个始发² Π _1/2和^2周Π _3/2在较高的振动能级的状态相比，是容易而以较低的水平来测量。a的辐射寿命约为10 ⁰ – 10 ³和10 ⁰ – 10 ² s。² Π _1/2和^2个Π _3/2分别状态。计算了所有偶极允许跃迁的谱带起源，Franck-Condon因子和爱因斯坦A系数。辐射寿命的与旋转角度量子数改变分配进行了研究为A ⁴ Π，B ⁴ Σ ^-，2 ⁴ Π，B ² Σ ^- ，和d ^2点Σ ⁺的状态。这项工作中报告的过渡特性可以为将来的实验和理论研究提供有用的指导。