Geological archives record multiple reversals of Earth’s magnetic poles, but the global impacts of these events, if any, remain unclear. Uncertain radiocarbon calibration has limited investigation of the potential effects of the last major magnetic inversion, known as the Laschamps Excursion [41 to 42 thousand years ago (ka)]. We use ancient New Zealand kauri trees (Agathis australis) to develop a detailed record of atmospheric radiocarbon levels across the Laschamps Excursion. We precisely characterize the geomagnetic reversal and perform global chemistry-climate modeling and detailed radiocarbon dating of paleoenvironmental records to investigate impacts. We find that geomagnetic field minima ~42 ka, in combination with Grand Solar Minima, caused substantial changes in atmospheric ozone concentration and circulation, driving synchronous global climate shifts that caused major environmental changes, extinction events, and transformations in the archaeological record.

A systematic characterization of gas phase binary prenucleation complexes between HSO (SA) and other molecules present in the atmosphere (NH, (CH)NH, (CH)NH, (CH)N, HO, (CH)OH, (CH)O, HF, CH F, PH, (CH)PH, (CH)PH, (CH)P, HS, (CH)SH, (CH)S, HCl, (CH)Cl) has been carried out using the ωB97X-D/6-311++(2d,2p) method at the DFT level of theory. A relationship between the energy gap of the SA's LUMO and the partner molecule's HOMO, and the increasing number of methyl groups -CH in the SA's partner molecule is provided. The binding energies of the bimolecular complexes are found to be related to the electron density in the hydrogen bond critical point, the HOMO-LUMO energy gap, the nature of the hydrogen acceptor atom, and the frequencies shift of acid OH bonds. The results show how the frontier orbital compatibility determines the binding energy and that the properties of SA's OH bond which remains free of interactions are affected by the bimolecular adduct formation.

A systematic characterization of the frontier molecular orbitals (FMO) of gas-phase prenucleation complexes between H 2 SO 4 and other molecules present in the atmosphere (NH 3 , H 2 O, (CH 3)OH, HF, (CH 3) 2 PH, (CH 3)SH) is carried out using the ωB97X-D/6-311++(2d,2p) method at the density functional theory level of theory. The FMO theory principles are taken into account to gain insight into the nature of intermolecular interactions. The results show that the highest occupied molecular orbital/lowest unoccupied molecular orbital molecular system characterization can be adopted as a complementary tool of analysis in supporting the study of atmospheric prenucleation processes. It is shown that the stability and the spatial arrangement of molecular systems can be also thought in terms of inter-and intra-molecular energy gaps ΔE HL that play an important role in the development of association processes.