第一性原理对VO_x^(1-)(x=1～5)阴离子团族结构及稳定性的研究

Fist principles calculations on the structures and stabilities of the VO_x^(1-)(x=1～5) Molecular Ions

用密度泛函理论(DFT)的B3LYP方法,V的内层10个电子用相对论有效实势(RECP)近似,氧原子用全电子基组6-311++g(d,p),V的价电子用lanl2dz基组,对气态VOx1-(x=1~5)分子的几何构型、振动频率、垂直电子亲和能、垂直电离能和能级分布进行了理论研究.该系列分子的基态电子态为:VO1-(3Σ),VO21-(3B1),VO31-(1A′1),VO41-(1A1),VO51-(3A).VO31-分子基态的几何构型为平面分子,没有John-Teller效应或Renner-Teller效应.而VO41-、VO51-分子的基态都是立体结构,存在明显的John-Teller和Renner-Teller效应,对称性降低,稳定性增加.该系列分子离子基态结构的垂直电离能分别为:1.052eV,2.085 eV,4.690 eV,4.460 eV,5.046 eV,该结果表明该系列分子离子的氧原子数从3增加到5时,垂直电离能没有明显改变.垂直电子亲和能也大致有这个规律,但由于该系列分子离子是负离子,对电子有排斥,它们得到一个电子都需要外加能量,其垂直电子亲和能都为负值.VO51-(3A)的垂直电子亲和能最大,吸收一个电子需要的能量最小.能级分布研究表明:VO21-比VO1-稳定,氧原子数从3增加到5,稳定性没有明显变化.

The geometric configurations, vibration frequencies, vertical electron affinity energy, vertical ionization energies and energy levels of gaseous VOx^1- （x = 1- 5） were calculated with a B3LYP method under relativistic effective core potential （RECP） （O/6-311 ＋ ＋ g（d,p） ,V/LANL2DZ）. The calculations show that the electronic ground states of the series molecules are as follows： VO^1-（^3∑）,VO^1-（^3B1）,VO3^1-（ ^1A＇1） , VO4^1-（^1A1） and VO5^1-（^3A） .The geometric configuration of the ground state VO3^1- is planar;which has no John-Teller or Renner-Teller effect. VO4^1- and VO5^1- are stereo-structures, which exhibit obvious John-Teller or Rennet-Teller effect, that is, the higher the stability is, the lower the symmetry is. The vertical ionization energies of this series molecular ions are 1.052 eV,2.085 eV,4.690 eV,4.460 eV,5.046 eV respectively, and the vertical ionization energies, the vertical electronic affinity energies and the stabilities of VOx^1-（x = 3- 5） are of no significant difference. VO5^1-（^3A） has the biggest vertical electronic affinity among these molecular ions;it needs the fewest energy to absorb an electron among these molecular ions; all the vertical electronic affinities of these molecular ions are negative for they are negative ions and the exclusion of electrons in these molecular ions. The results show that VO2^1- are more stable than VO^1 -, and the stabilities of VOx^1- （ x = 3 - 5） are of no significant difference.