AlO自由基在辐射场中的物理和光谱特性

AlO自由基在金属有机化学、催化材料、燃烧化学及天体物理学等领域受到人们的广泛关注,研究外辐射场下对AlO自由基的物理特性和光谱特征的影响将有助于更深入理解和增强在相关领域的应用。采用密度泛函理论B3PW91方法,在6-311+G(3df,2p)基组水平上优化了不同辐射场(-0.04~0.04 a.u.)下AlO自由基的基态稳定构型,用同样方法计算了该构型的分子结构、总能量、能隙以及红外光谱、拉曼光谱、紫外可见吸收光谱受外辐射场的影响。结果表明,分子结构与辐射场有关。在外辐射场变化范围(-0.04~0.04 a.u.),自由基总能先小幅度增大(-0.03 a.u.达到最大值)后大幅度单调减小;分子键长在负辐射场(-0.04~0 a.u.)没有明显变化,但在(0~0.04 a.u.)正辐射场下单调变长;偶极矩先减小(-0.03 a.u.达到最小值)后增大;而能隙先不断增大(-0.04^-0.02 a.u.),在(-0.02~0.03 a.u.)辐射场能隙基本稳定,随后单调下降。正辐射场(0~0.04 a.u.)对AlO自由基的振动频率和红外强度的影响较大, AlO自由基在0.04 a.u.辐射场下的红外光谱红移74 cm^-1,其对应光谱强度是未加辐射场的80倍;正辐射场(0~0.04 a.u.)的拉曼光谱红移较明显,在0.04 a.u.红移78 cm^-1;负辐射场(0^-0.04 a.u.)对拉曼光谱影响也较大,在-0.03 a.u.辐射场下具有很强的拉曼活性是未加辐射场的688倍;正辐射场(0~0.04 a.u.)下AlO自由基的紫外可见吸收光谱中原来无辐射场下的最大吸收峰(170 nm)蓝移了22 nm且吸收幅度减至一半,在负辐射场范围内(0^-0.04 a.u.)该吸收峰也辐有蓝移其强度也有减弱趋势;AlO自由基的无辐射场下第二个最大紫外可见峰在正辐射场作用下,其波长从282 nm一直递减蓝移13 nm和吸收强度递增至2.2倍,负辐射场范围内(0^-0.04 a.u.)该吸收峰红移10 nm和吸收强度递增了6.2倍,超过了无辐射场下最大吸收波长强度。

Study on Physical Properties and Spectra of AlO in External Radiation Field

AlO radicals have attracted widespread attention in the fields of organometallic chemistry, catalytic materials, combustion chemistry and astrophysics. The study of the effects of external radiation on the physical and spectral properties of AlO radicals will help to further understand and enhance their applications in related fields. The density functional theory B3 PW91 method is used to optimize the ground state configuration of AlO radicals under different radiation fields(-0.04~0.04 a.u.) at the 6-311+G(3 df, 2 p) basis level. On this basis, the molecular structure, total energy, energy gap, infrared spectrum, Raman spectrum and ultraviolet-visible absorption spectrum of AlO radicals were calculated by the same method and level. The results show that under the action of external radiation field, the molecular structure changes obviously, and it has a strong dependence on the radiation field. The total energy of the molecule increases slightly and then monotonically decreases with the radiation field(the maximum is-0.03 a.u.). The bond length of molecule hardly changes significantly under the radiation field(-0.04~0 a.u.), but increases monotonously under the radiation field(0~0.04 a.u.). The dipole moment decreases first and then increases(the minimum is-0.03 a.u.). The energy gap increases first, and then stabilizes in the radiation field(-0.02~0.03 a.u.), and then decreases monotonously. The infrared spectra of AlO radicals under 0.04 a.u. radiation field are red-shifted by 74 cm^-1, and the corresponding spectral intensity is 80 times that of the non-radiation field. The strong Raman activity of AlO radicals under-0.03 a.u. radiation field is 688 times that of the non-radiation field. The UV-Vis absorption spectra of AlO radicals in the positive radiation field(0~0.04 a.u.) show that the maximum absorption wavelength of 170 nm in the non-radiation field is blue-shifted by 22 nm and the absorption intensity decreases to half, which is consistent with the trend of the absorption wavelength in the negative radiation field(0^-0.04 a.u.). The UV-Vis absorption spectra of AlO radicals in the directional radiation field(0~0.04 a.u.) show that the second maximum absorption wavelength(282 nm) is blue-shifted by 13 nm and the absorption intensity increases by 2.2 times compared with that in the non-radiation field, but in the negative radiation field(0^-0.04 a.u.), the absorption wavelength is red-shifted by 10 nm and the absorption intensity increases by 6.2 times, which exceeds the maximum absorption wavelength intensity in the non-radiation field.