Browsing by Author "Xu, Xuan"

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A Density Functional Theory Study on Nonlinear Optical Properties of Double Cage Excess Electron Compounds: Theoretically Design M[Cu(Ag)@(NH3)(n)](M = Be, Mg and Ca; n=1-3)
(2019-04-05)
Liang, Yan Ying
;
Li, Bo
;
Xu, Xuan
;
Gu, Feng Long
;
Zhu, Chaoyuan
In this work, we investigated the nonlinear optical (NLO) properties of excess electron electride molecules of M[Cu(Ag)@(NH3)(n)](M = Be, Mg and Ca; n = 1-3) using density functional theory (DFT). This electride molecules consist of an alkaline-earth (Be, Mg and Ca) together with transition metal (Cu and Ag) doped in NH3 cluster. The natural population analysis of charge and their highest occupied molecular orbital suggests that the M[Cu(Ag)@(NH3)(n)] compound has excess electron like alkaline-earth metal form double cage electrides molecules, which exhibit a large static first hyperpolarizability (beta(e)(0)) (electron contribution part) and one of which owns a peak value of beta(e)(0) 216,938 (a.u.) for Be [Ag@(NH3)(2)] and vibrational harmonic first hyperpolarizability [(beta(nr)(zzz)) (nuclear contribution part) values and the ratio of beta(nr)(zzz)/beta(e)(zzz'), namely, eta values from 0.02 for Be[Ag@(NH3)] to 0.757 for Mg [Ag@(NH3)(3)]. The electron density contribution in different regions on beta(e)(zzz) values mainly come from alkaline-earth and transition metal atoms by first hyperpolarizability density analysis, and also explains the reason why beta(e)(zzz) values are positive and negative. Moreover, the frequency-dependent values ss(-2 omega,omega,omega) are also estimated to make a comparison with experimental measures. (c) 2018 Wiley Periodicals, Inc.
Remarkable nonlinear optical response of excess electron compounds: theoretically designed alkali-doped aziridine M-(C2NH5)(n)
(2017-09-21)
Li, Bo
;
Xu, Chao
;
Xu, Xuan
;
Zhu, Chaoyuan
;
Gu, Feng Long
Theoretically designed alkali-doped aziridine M-(C2NH5)(n) (M = Li, Na and K; n = 1, 2, 3, and 4) are investigated by density functional theory (DFT) and time-dependent TD-DFT. The interaction energies at optimized electronic structures indicate that alkali-doped aziridine are quite stable. The natural population analysis of charges on alkali atoms show that all positive and electronic transitions to LUMO orbitals are large, so that the designed compounds not only have electride features, but also have large flexible ligands. This leads to a high-performance nonlinear optical response (NLO) and this remarkable NLO response mainly comes from alkali atoms. By calculating the first hyperpolarizabilities for M-(C2NH5)(4) with M@ Calix[4] pyrrole for comparison, we demonstrate that enhancements of the NLO response of M-(C2NH5)(4) are 10 to 100 times larger than those of M@ Calix[ 4] pyrrole, and in particular, the largest first hyperpolarizability values of Na-(C2NH5)(4) is up to 3.4 x 10(6) (a. u.).