理論研究鈹團簇結(jié)構(gòu)及性質(zhì)的碳摻雜效應(yīng)
發(fā)布時間：2018-11-14 07:45
【摘要】：在B3PW91/6-311+G(d)水平下優(yōu)化得到了Ben C(n=1 12)團簇和純鈹團簇的最低能量結(jié)構(gòu),并對它們的結(jié)構(gòu)特點進行對比。結(jié)果表明摻雜的碳原子優(yōu)先位于鈹團簇的表面且趨向于形成四配位的化合物,其中例外的是Be6C中碳原子與三個鈹原子成鍵,這可以歸因于Be6團簇非常穩(wěn)定的八面體結(jié)構(gòu),如果碳原子與四個鈹原子成鍵就會使穩(wěn)定的八面體結(jié)構(gòu)遭到破壞;除Be C的最低能量結(jié)構(gòu)為三重態(tài)以外,其它所有n=2 12的團簇最穩(wěn)定結(jié)構(gòu)都為單重態(tài);另外,除n=4、5和6以外其它所有Ben C團簇的最低能量結(jié)構(gòu)與對應(yīng)的Ben+1團簇的最低能結(jié)構(gòu)構(gòu)型相似。在Ben C團簇的最低能量結(jié)構(gòu)基礎(chǔ)上,使用QCISD(T)方法計算了它們的電子和能量性質(zhì):結(jié)合能(Eb)、二階能量分差(Δ2E)、解離能(ΔE)、HOMO-LUMO能隙值等。其中Ben C團簇系列中每一個分子的結(jié)合能都比對應(yīng)的Ben+1團簇的大,這說明碳原子的引入增加了純鈹團簇內(nèi)部的相互作用。此外,Be3C和Be8C在結(jié)合能(Eb)、二階能量分差(Δ2E)、垂直電離能(VIPs)等性質(zhì)演變中表現(xiàn)出特殊的穩(wěn)定性從而被看作是幻數(shù)結(jié)構(gòu)。對兩團簇的分子軌道分析可以看出兩團簇都是全充滿的電子殼層結(jié)構(gòu),Be3C的電子殼層結(jié)構(gòu)為1S21P62S2,Be8C的電子殼層結(jié)構(gòu)為1S21P61D42S21D6,都符合jellium模型,這進一步證明它們特殊的穩(wěn)定性。而相對于純鈹團簇而言,碳原子軌道的貢獻導致分子軌道能級發(fā)生了改變,Be8C中碳摻雜使2S軌道能級低于其中的三個D軌道,Be3C中碳摻雜使2S軌道能級低于1D的軌道能級。
[Abstract]:At the B3PW91/6-311 G (d) level, the lowest energy structures of Ben C (nni1 / 12) cluster and pure beryllium cluster are obtained, and their structural characteristics are compared. The results show that the doped carbon atoms are preferentially located on the surface of beryllium clusters and tend to form four-coordinated compounds, except that the carbon atoms in Be6C bond with three beryllium atoms, which can be attributed to the very stable octahedron structure of the Be6 cluster. If carbon atoms bond with four beryllium atoms, the stable octahedron structure will be destroyed. Except that the lowest energy structure of Be C is triplet, the most stable structure of all the other clusters is singlet. In addition, the lowest energy structure of all the Ben C clusters except ndl4 and 6 is similar to that of the corresponding Ben 1 clusters. On the basis of the lowest energy structure of Ben C clusters, the electron and energy properties of Ben C clusters are calculated by QCISD (T) method: second order energy difference of binding energy (螖 2e), dissociation energy (螖 E), HOMO-LUMO energy gap), etc. The binding energy of each molecule in the Ben C cluster is higher than that of the corresponding Ben 1 cluster, which indicates that the introduction of carbon atoms increases the interaction within the pure beryllium cluster. In addition, Be3C and Be8C show special stability in the evolution of the second order energy difference (螖 2e) and vertical ionization energy (VIPs) of binding energy (Eb), so they are regarded as magic number structures. The molecular orbital analysis of the two clusters shows that both clusters are full of electronic shell structure, and the electronic shell structure of Be3C is 1S21P62S2S2Be8C, which accords with the jellium model, which further proves their special stability. Compared with pure beryllium clusters, the contribution of carbon atom orbital leads to the change of molecular orbital energy level. Carbon doping in Be8C makes the energy level of 2S orbit lower than that of three D orbitals, and carbon doping in Be3C makes the energy level of 2S orbital lower than that of 1D.
【學位授予單位】：吉林大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：O641.1
本文編號：2330516
[Abstract]:At the B3PW91/6-311 G (d) level, the lowest energy structures of Ben C (nni1 / 12) cluster and pure beryllium cluster are obtained, and their structural characteristics are compared. The results show that the doped carbon atoms are preferentially located on the surface of beryllium clusters and tend to form four-coordinated compounds, except that the carbon atoms in Be6C bond with three beryllium atoms, which can be attributed to the very stable octahedron structure of the Be6 cluster. If carbon atoms bond with four beryllium atoms, the stable octahedron structure will be destroyed. Except that the lowest energy structure of Be C is triplet, the most stable structure of all the other clusters is singlet. In addition, the lowest energy structure of all the Ben C clusters except ndl4 and 6 is similar to that of the corresponding Ben 1 clusters. On the basis of the lowest energy structure of Ben C clusters, the electron and energy properties of Ben C clusters are calculated by QCISD (T) method: second order energy difference of binding energy (螖 2e), dissociation energy (螖 E), HOMO-LUMO energy gap), etc. The binding energy of each molecule in the Ben C cluster is higher than that of the corresponding Ben 1 cluster, which indicates that the introduction of carbon atoms increases the interaction within the pure beryllium cluster. In addition, Be3C and Be8C show special stability in the evolution of the second order energy difference (螖 2e) and vertical ionization energy (VIPs) of binding energy (Eb), so they are regarded as magic number structures. The molecular orbital analysis of the two clusters shows that both clusters are full of electronic shell structure, and the electronic shell structure of Be3C is 1S21P62S2S2Be8C, which accords with the jellium model, which further proves their special stability. Compared with pure beryllium clusters, the contribution of carbon atom orbital leads to the change of molecular orbital energy level. Carbon doping in Be8C makes the energy level of 2S orbit lower than that of three D orbitals, and carbon doping in Be3C makes the energy level of 2S orbital lower than that of 1D.
【學位授予單位】：吉林大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：O641.1
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