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Ceometries, Energetics and Spectroscopic Properties of Oxygen Clusters Oxy (x=2~6, y=-2~2)
Yi Jun, Chen Hongbo, Wei Guang, Lin Yinzhong, Liao Daiwei
Department of Chemistry, Department of Oceanography, State Key Lab ofPhysical Chemistry on Solid Surfaces, Institute ofPhysical Chemistry, Xiamen University, Xiamen 361005
Abstract:
The geometries, energetics and spectroscopic properties of oxygen clusters, Oxy(x=2~6, y=-2~2), were investigated at the B3LYP/6-311G (d, p) level. The CASSCF calculations were carried out for the ground and excited states of3O2and2O2+. The total energy is3O2(3Σg-)<2O2-(2Πgi)<1O2(1Δg)<1O2-2(1Σg+)<2O2+(2Πg)<1O2+2(1Σg+). The relative energy of the active doublet anion of oxygen molecule,2O2-(2Πgi), is only 28 kJ/mol higher than the triplet neutral oxygen molecule,3O2(3Σg-). The calculated O-O vibrational frequencies all are in good agreement with the experimental values. They are 1577 (1580), 1139 (1090), 1563 (1484), 627 (615~545) and 1993 (1905) cm-1, where the O-O vibrational frequency values in parentheses are experimental values, for3O2(3Σg-),2O2-(2Πgi),1O2(1Δg),1O2-2(1Σg+) and2O2+(2Πg), respectively. Moreover, the O-O vibrational frequency of1O2+2(1Σg+) was computed as 2368 cm-1which has not been reported before at both experimental and theoretical levels. Both bent and linear geometries of O3were studied. The bent-types of O3are more favorable than the linear-type in energy. Three types of structure for oxygen trimers are calculated at the B3LYP/6-311G (d, p) level. They are the structure-I with an obtuse angle of O-O-O,the structure-II with an acute angle of O-O-O, and the structure-III of linear type. For a bent-type structure of O3species (structure-I), the total enegy is2O3-(2B1)<1O3(1A1)<3O3(3B2)<1O3-2(1A1)<2O3+(2A1). The optimization of geometry at B3LYP/6-311G (d, p) level indicated that the species of2O3-(2B1) with 1.3573 of O-O bond length and 115.6584o of O-O-O bond anger is the ground state of O3. The total energy of O4species and their ions is2O4-(Cs,2A′, bend-type)<2O4-(C2v,2A2,face-centered triangle-type)<2O4-(D∞h,2Σg, linear-type)<1O4(Cs,1A′, bend-type)<1O4(D∞h,1Σg, linear-type)<1O4(D4h,1A1g, square-type)<1O4(C2v,1A1, face-centered triangle-type)<2O4-(D4h,1A1g, square-type)<2O4+(D∞h,2Σg, linear-type)<2O4+(Cs,1A′, bend-type). The species with the lowest relative energy is an anion,2O4-(Cs,2A′, bendtype), with chair form geometry and characteristic vibronic frequencies of 1179 and 1349 cm-1. The relative energy of1O5(C2v,1A1) with coplanar-triangle-bicone geometry is the lowest among the O5species and their ions, which may be a resonance structure with1O5(C2v,1A1) of A type. Their characteristic vibronic frequency is 1302 cm-1. The relative energy of the O6species and their ions with hexagon geometry is lower than one with linear geometry. Their infrared vi-bronic intensity may be weak and unobservable but the Raman vibronic intensity may be strong and observable based on their symmetry.
Key words:  Oxygen cluster, O2, O3, O4, O5, O6, ab initio, Spectroscopic properties, Geome-try, Energetics
FundProject:国家自然科学基金资助项目(29773037)
附件
氧原子簇Oxy (x=2~6, y=-2~2)的结构、能学与光谱性质
易军, 陈鸿博, 魏光, 林银钟, 廖代伟
厦门大学物理化学研究所,化学系,海洋系,固体表面物理化学国家重点实验室,厦门 361005
摘要:
在B3LYP/6-311G(d,p)水平上,对氧原子簇Oxy(x=2~6,y=-2~2)的结构、能学与光谱性质进行了量子化学从头计算,对3O2和2O2+的基态和激发态进行了CASSCF计算.结果表明,氧分子及其离子的体系总能量大小为<O2+(2Пg)<1O2+2(1∑g+).活性的二重态氧分子负离子2O2-(2Пgi)在相对能量上只比三重态的中性氧分子3O2(3Σg-)高28kJ/mol.对于弯曲型(Structure-I)的臭氧分子(O3)及其离子,其体系总能量相对次序为2O3-(2B1)<1O3(1A1)<3O3(3B2)<1O3-2(1A1)<2O3+(2A1).氧四聚体(O4)及其离子的体系总能量相对大小为2O4-(C8弯曲型,2A′)<2O4-(C2v面心三角型,2A2)<2O4-(D∞h直线型,2∑g)<1O4(C8弯曲型,1A′)<1O4(D∞h直线型,1∑g)<1O4(D4h正方型,1A1g)<1O4(C2v面心三角型,1A1)<2O4-(D4h正方型,1A1g)<2O4+(D∞h直线型,2∑g)<2O4+(C8弯曲型,1A′).相对能量最低的氧四聚体物种是呈椅形的带一个负电荷的负离子2O4-(C8弯曲型,2A′),其特征振动频率应出现在1179和1349cm-1.共面三角双锥型的1O5(C2v,1A1)相对能量最低,其与A字型(C2v,1A1)可能是共振构型,特征振动频率位于1302cm-1.氧六聚体(O6)的六边型构型的相对能量较低,其振动频率的红外强度很弱,但从其对称性看,应具有较强的拉曼强度.以B3LYP/6-311G(d,p)方法计算、并经0.9614因子校正的氧分子及其离子的O-O振动频率与实验值相当吻合.
关键词:  氧簇  O2  O3  O4  O5  O6  ab initio  光谱性质  结构  能学
DOI:10.1088/1674-0068/14/1/65-74
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