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Register a new userRelativistic effects for the superheavy reaction Og + 2Ts$_2$ -> Og(Ts)$_4$ : Dramatic relativistic effects for the atomization energy of Oganesson tetratennesside Og(Ts)$_4$ and the prediction of the existence of tetrahedral Og(Ts)$_4$
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Our all-electron fully relativistic Dirac-Fock (DF) and nonrelativistic (NR) Hartree-Fock (HF) SCF molecular calculations for the superheavy tetrahedral (T$_d$) oganesson tetratennesside OgT$_4$ predict atomization energy (Ae) of 7.45 and -11.21 eV, respectively. Our DF and NR calculations, however for the square planar (D$_{4h}$)OsTs$_4$ predict atomization energy (Ae) o 6.34 and -8.56 ev, respectively. There are dramatic relativistic effects for the atomization energy of T$_d$ and D$_{4h}$ OgT$_4$ of -18.65 eV and 14.90 eV, respectively. Whereas our DF calculations predict the T$_d$OgT$_4$ to be more stable than the D$_{4h}$ OgT$_4$ by ~1.10 eV, our NR calculations predict the D$_{4h}$ OgT$_4$ to be more stable than the T$_d$ OgT$_4$ by ~2.65eV. Our NR calculations predict both the T$_d$ and D$_{4h}$ OgTs$_4$ to be unbound by 11.21 and 8.56 eV, respectively. However our relativistic DF calculations predict both the T$_d$ and D$_{4h}$ OgT$_4$ to be bound by 7.45 and 6.34 eV respectively and so the relativistic treatment is mandatory for bonding and binding in the pentatomic superheavy system with 586 electrons involving the two heaviest SHE Ts and Og.
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Our gargantuan ab initio all-electron fully relativistic Dirac-Fock (DF), nonrelativistic (NR) Hartree-Fock(HF) and Dirac-Fock-Breit-Gaunt(DFBG) molecular SCF calculations for the superheavy octahedral Oganesson hexatenniside OgTs$_6$ predict atomization energy (Ae) of 9.47, -5.54and 9.37 eV, at the optimized Os-Ts bond distances of 3.35, 3.34 and 3.36 angstroms, respectively. There are dramatic effects of relativity for the atomization energy of OgTs$_6$ (with seven superheavy elements and 820 electrons) of ~ 15.0 eV each at both the DF and DFBG levels of theory, respectively. Our calculated energy of reaction for the titled superheavy reaction Og + 3Ts$_2$ -> OgTs$_6$ at the DF, NR and DFBG levels of theory is 6.33, 8.81, and 6.26 eV, respectively. Mulliken analysis as implemented in the DIRAC code for our DF and NR calculations (using the dyall.ev4z basis) yields the charges Og(+0.60) and Og(+0.96), respectively on the central Og atom indicating that our relativistic DF calculations predict octahedral OgTs$_6$ to be less ionic. However, due caution must be used to interpret the results of Mullikens population analysis, which is highly basis set dependent.
Our all electron (DFBG) calculations show differences between relativistic and non-relativistic calculations for the structure of the isomers of Og(CO)6
According to theory, cluster radioactivity becomes an important decay mode in superheavy nuclei. In this work, we predict that the strongly-asymmetric fission, or cluster emission, is in fact the dominant fission channel for $^{294}_{118}$Og$_{176}$, which is currently the heaviest synthetic isotope known. Our theoretical approach incorporates important features of fission dynamics, including quantum tunneling and stochastic dynamics up to scission. We show that, despite appreciable differences in static fission properties such as fission barriers and spontaneous fission lifetimes, the prediction of cluster radioactivity in $^{294}_{118}$Og$_{176}$ is robust with respect to the details of calculations, including the choice of energy density functional, collective inertia, and the strength of the dissipation term.
We report resistance and elastoresistance measurements on (Ba$_{0.5}$K$_{0.5}$)Fe$_2$As$_2$, CaKFe$_4$As$_4$, and KCa$_2$Fe$_4$As$_4$F$_2$. The Fe-site symmetry is $D_{2d}$ in the first compound but $C_{2v}$ in the latter two, which lifts the degeneracy of the Fe $d_{xz}$ and $d_{yz}$ orbitals. The temperature dependence of the resistance and elastoresistance is similar between the three compounds. Especially, the [110] elastoresistance is enhanced with decreasing temperature irrespective of the Fe-site symmetry. This appears to be in conflict with recent Raman scattering studies on CaKFe$_4$As$_4$, which suggest the absence of nematic fluctuations. We consider possible ways of reconciliation and suggest that the present result is important in elucidating the origin of in-plane resistivity anisotropy in iron-based superconductors.
Recent two-stream deep Convolutional Neural Networks (ConvNets) have made significant progress in recognizing human actions in videos. Despite their success, methods extending the basic two-stream ConvNet have not systematically explored possible network architectures to further exploit spatiotemporal dynamics within video sequences. Further, such networks often use different baseline two-stream networks. Therefore, the differences and the distinguishing factors between various methods using Recurrent Neural Networks (RNN) or convolutional networks on temporally-constructed feature vectors (Temporal-ConvNet) are unclear. In this work, we first demonstrate a strong baseline two-stream ConvNet using ResNet-101. We use this baseline to thoroughly examine the use of both RNNs and Temporal-ConvNets for extracting spatiotemporal information. Building upon our experimental results, we then propose and investigate two different networks to further integrate spatiotemporal information: 1) temporal segment RNN and 2) Inception-style Temporal-ConvNet. We demonstrate that using both RNNs (using LSTMs) and Temporal-ConvNets on spatiotemporal feature matrices are able to exploit spatiotemporal dynamics to improve the overall performance. However, each of these methods require proper care to achieve state-of-the-art performance; for example, LSTMs require pre-segmented data or else they cannot fully exploit temporal information. Our analysis identifies specific limitations for each method that could form the basis of future work. Our experimental results on UCF101 and HMDB51 datasets achieve state-of-the-art performances, 94.1% and 69.0%, respectively, without requiring extensive temporal augmentation.
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