论文部分内容阅读
c-C_3H_2,HCCH和H_2CCC的电离能用CCSD(T)／CBS方法进行了计算。在计算中还包含了零点振动能校正和芯电子和价电子相关校正,标量相对论效应和高于CCSD(T)理论水平的校正。CCSD(T)／CBS方法计算的c-C_3H_2和HCCH电离能的数值分别为(9.15±0.03)和(8.96±0.04)eV,且与实验值(9.15±0.03)和(8.96±0.04)eV很好一致。CCSD(T)计算的H_2CCC→H_2CCC~+(~2A_1,C_(2v))和H_2CCC→H_2CCC+(~2A′,C_s)电离跃迁的电离能分别为10.477和10.388 eV。在考虑Frank-Condon因子基础上,以前单光子电离实验所测定的(10.43±0.02)eV电离能最可能对应于H_2CCC→H_2CCC+(~2A_1,C_(2v))跃迁的电离阈值。虽然对c-C_3H_2,HCCH和H_2CCC实验电离能测量的精确性难以达到理论计算精度的±30 meV范围内,所得到的理论电离能值与实验值非常一致,表明CCSD(T)／CBS计算结合高级相关校正对简单的碳氢卡宾和双自由基能得到可靠的电离能预示值。还给出了c-C_3H_2／c-C_3H_2~+,HCCH／HCCH+和H_2CCC／H_2CCC+在0和298 K的生成热△H_(f0)~o和△H_(f298)~o。发现考虑实验精度不确定性后,它们的实验值与CCSD(T)／CBS预示值非常一致。
The ionization of c-C_3H_2, HCCH and H_2CCC can be calculated by CCSD (T) / CBS method. Zero vibration energy correction and core-electron and valence-electron correlation corrections, scalar relativistic effects, and corrections higher than the theoretical level of CCSD (T) are also included in the calculations. The values of c-C 3 H 2 and HCCH ionization energies calculated by the CCSD (T) / CBS method were (9.15 ± 0.03) and (8.96 ± 0.04) eV, respectively, and were positively correlated with the experimental values of 9.15 ± 0.03 and 8.96 ± 0.04 eV Alright. The ionization energies of H_2CCC → H_2CCC ~ + (~ 2A_1, C_ (2v)) and H_2CCC → H_2CCC + (~ 2A ’, C_s) calculated by CCSD (T) were 10.477 and 10.388 eV, respectively. Based on the Frank-Condon factor, the (10.43 ± 0.02) eV ionization energy determined by the previous single-photon ionization experiment most likely corresponds to the ionization threshold of the H 2 CCC → H 2 CCC + (~ 2A_1, C 2v) transition. Although the accuracy of the ionization energy measurements of c-C_3H_2, HCCH and H_2CCC experiments is hard to reach the theoretical calculation accuracy of ± 30 meV, the theoretical ionization energy obtained is in good agreement with the experimental data, indicating that the combination of CCSD (T) / CBS calculations Advanced correlation corrections give reliable predictions of ionization energy for simple hydrocarbon carbenes and diradicals. The formation heat ΔH_ (f0) ~ o and ΔH_ (f298) ~ o of c-C_3H_2 / c-C_3H_2 ~ +, HCCH / HCCH + and H_2CCC / H_2CCC + at 0 and 298 K are also given. After considering the uncertainties of experimental accuracy, they found that the experimental values were in good agreement with the CCSD (T) / CBS predictions.