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1. Molecular square dancing in CO-CO collisions

   https://doi.org/10.1126/science.aan2729  

   Sun, Zhong-Fa ; van Hemert, Marc C. ; Loreau, Jérôme ; van der Avoird, Ad ; Suits, Arthur G. ; Parker, David H. ( July 2020 , Science)

   null (Ed.)

   Knowledge of rotational energy transfer (RET) involving carbon monoxide (CO) molecules is crucial for the interpretation of astrophysical data. As of now, our nearly perfect understanding of atom-molecule scattering shows that RET usually occurs by only a simple “bump” between partners. To advance molecular dynamics to the next step in complexity, we studied molecule-molecule scattering in great detail for collision between two CO molecules. Using advanced imaging methods and quasi-classical and fully quantum theory, we found that a synchronous movement can occur during CO-CO collisions, whereby a bump is followed by a move similar to a “do-si-do” in square dancing. This resulted in little angular deflection but high RET to both partners, a very unusual combination. The associated conditions suggest that this process can occur in other molecule-molecule systems. 

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2. Exploring the Enhancement of Exchange Bias in Innovative Core/Shell/Shell Structures: Synthesis and Magnetic Properties of Co-Oxide/Co and Co-Oxide/Co/Co-Oxide Inverted Nanostructures

   https://doi.org/10.3390/nano13050880  

   Ghoshani, Maral ; Mozaffari, Morteza ; Acet, Mehmet ; Hosseini, Mahshid ; Vashaee, Daryoosh ( March 2023 , Nanomaterials)

   In this study, we investigate the enhancement of exchange bias in core/shell/shell structures by synthesizing single inverted core/shell (Co-oxide/Co) and core/shell/shell (Co-oxide/Co/Co-oxide) nanostructures through a two-step reduction and oxidation method. We evaluate the magnetic properties of the structures and study the effect of shell thickness on the exchange bias by synthesizing various shell thicknesses of Co-oxide/Co/Co-oxide nanostructures. The extra exchange coupling formed at the shell–shell interface in the core/shell/shell structure leads to a remarkable increase in the coercivity and the strength of the exchange bias by three and four orders, respectively. The strongest exchange bias is achieved for the sample comprising the thinnest outer Co-oxide shell. Despite the general declining trend of the exchange bias with Co-oxide shell thickness, we also observe a nonmonotonic behavior in which the exchange bias oscillates slightly as the shell thickness increases. This phenomenon is ascribed to the dependence of the antiferromagnetic outer shell thickness variation at the expense of the simultaneous opposite variation in the ferromagnetic inner shell. 

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3. Rejoinder: “Co-citation and Co-authorship Networks of Statisticians”

   https://doi.org/10.1080/07350015.2022.2055358  

   Ji, Pengsheng ; Jin, Jiashun ; Ke, Zheng Tracy ; Li, Wanshan ( April 2022 , Journal of Business & Economic Statistics)
4. Forest carbon offsets include co‐benefits and co‐detriments

   https://doi.org/10.1002/fee.2018  

   Hastings, Sarah ; Laflower, Danelle ; Thompson, Jonathan R. ( April 2019 , Frontiers in Ecology and the Environment)
5. The excitation of CO in CO-dominated cometary comae

   https://doi.org/10.1093/mnras/stad268  

   Żółtowski, M. ; Lique, F. ; Loreau, J. ; Faure, A. ; Cordiner, M. ( January 2023 , Monthly Notices of the Royal Astronomical Society)

   An abundance of CO significantly surpassing the abundance of H2O is observed in the comae of comets at large heliocentric distances. In these environments, CO molecules can be the most abundant species and they may be therefore the dominant projectiles inducing collisional excitation of the cometary molecules. It is thus of high interest to investigate the excitation of CO by CO. This article provides a new set of CO–CO collisional rate coefficients for temperatures up to 150 K and for CO rotational levels j1 up to 10. These data are obtained from quantum scattering calculations using the coupled states approximation. They are used in a simple radiative transfer model in order to test their impact on the excitation of cometary CO. Because mutual (de-)excitations of the target and projectile are important, the CO projectile was assumed to be thermalized at the kinetic temperature. We found that the non-local thermodynamical equilibrium regime extends for CO densities in the range 103–107 cm−3. We also observed that as soon as the CO/H2O ratio is larger than 70 per cent/30 per cent, the contribution of H2O collisions can be neglected. Similarly, the excitation of CO by CO may be ignored for relatively low CO/H2O density ratios (≤30 per cent/70 per cent). Finally, when the coma is a ∼50 per cent/50 per cent mixture of CO and H2O, the contribution of both colliders is similar and has to be considered.

    

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