Attention-based investigation and solution to the trade-off issue of adversarial training.

Adversarial training has become the mainstream method to boost adversarial robustness of deep models. However, it often suffers from the trade-off dilemma, where the use of adversarial examples hurts the standard generalization of models on natural data. To study this phenomenon, we investigate it from the perspective of spatial attention.

A theoretical survey on the structures, energetics, and isomerization pathways of the B(5)O radical.

Boron-centered radicals have received growing interest. Recently, two groups reported density functional theory investigations (GGA-PW91 and B3LYP) on a hexa-atomic boron-oxide radical, B(5)O, which has led to great discrepancies on the type of low-lying structures. In this article, we not only explore the energetics of doublet and quartet B(5)O isomers at high electron-correlated levels (CCSD(T)/6-311+G(2df), CCSD(T)/aug-cc-pVTZ, and G3B3) but also investigate the isomerization and fragmentation stability of the low-lying B(5)O isomers.

Pentaatomic planar tetracoordinate carbon molecules [XCAl(3)](q) [(X,q) = (B,-2), (C,-1), (N,0)] with C-X multiple bonding.

Among the fascinating planar tetracoordinate carbon (ptC) species, pentaatomic molecules belong to the smallest class, well-known as "pptC". It has been generally accepted that the planarity of pptC structure is realized via the "delocalization" of the p(z) lone pair at the central carbon and the ligand-ligand bonding interaction. Although "localization" is as key driving force in organic chemistry as "delocalization", the "localization" concept has not been applied to the design of pptC molecules, to the best of our knowledge.

Is the planar hexacoordinate nitrogen molecule NB(6)(-) viable?

Molecules with hypercoordinate planar centers have continued to receive enthusiastic attention due to their violation of the traditional models of three-dimensional chemical bonding and maximum tetracoordination. These electronic exotic but structurally aesthetic species have been optimistically conceived as building blocks in cluster-assembly for bulky materials. Recently, the planar hexacoordinate nitrogen (phN) unit, NB(6)(-), has been theoretically incorporated into a series of sandwich-like transition-metal compounds.

Understanding the borane analogy in Al(n)H(n+4) (n = 5-19): unprecedented stability of a non-Wade-Mingos cluster Al(8)H(12) fused by two T(d)-like Al(4)H(6).

Contrasting the boranes B(n)H(n+4) with rich chemistry, the alanes Al(n)H(n+4) remain largely unknown in laboratory, except for the simplest Al(2)H(6). Though recent experimental and theoretical studies have proved Al(n)H(n+2) to be the borane analogues, whether or not the borane analogy can exist for the more complicated Al(n)H(n+4) is still unclear. In this paper, we find that at the B3PW91/TZVP level, Al(n)H(n+4) each has a nido-single cluster ground structure as B(n)H(n+4) for n < 12.

Cluster-assembled compounds comprising an all-metal subunit Li3Al4-.

The recent, experimentally-discovered, all-metal antiaromatic Li3Al4- has attracted great interest and extensive investigations due to its unique chemical bonds and exotic properties. Although a very recent theoretical study demonstrated that the all-metal species Li3Al4- can be effectively stabilized by complexation with 3d transition metals, unfortunately such stabilization is at the expense of losing antiaromaticity (rectangular Al4) to become aromatic (square Al4). Here, we predict theoretically a series of cluster-assembled compounds [DM(Li3Al4)]q- (D=Li3Al4-, Cp-; M=Li, Na, K, Be, Mg, Ca).