Low-temperature, metastable electrochromism has been used as a tool to assign pigments in Photosystem I (PS I) from Thermosynechococcus vulcanus and both the white light and far-red light (FRL) forms of Chroococcidiopsis thermalis. We find that a minimum of seven pigments is required to satisfactorily model the electrochromism of PS I. Using our model, we provide a short list of candidates for the chlorophyll f pigment in FRL C. thermalis that absorbs at 756 nm, whose identity, to date, has proven to be controversial. Specifically, we propose the linker pigments A40 and B39 and two antenna pigments A26 and B24 as defined by crystal structure 1JB0. The pros and cons of these assignments are discussed, and we propose further experiments to better understand the functioning of FRL C. thermalis.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1063/5.0100431 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Crystallography of the litharge to massicot phase transformation from neutron powder diffraction data.
Acta Crystallogr B Struct Sci Cryst Eng Mater
February 2025
CSIRO Division of Mineral Products, Port Melbourne, Victoria, Australia.
The crystallographic phase change from tetragonal litharge (α-PbO; P4/nmm) to orthorhombic massicot (β-PbO; Pbcm) has been studied by full-matrix Rietveld analysis of high-temperature neutron powder diffraction data collected in equal steps from ambient temperature up to 925 K and back down to 350 K. The phase transformation takes place between 850 and 925 K, with the coexisting phases having equal abundance by weight at 885 K. The product massicot remains metastable on cooling to near ambient temperature.
View Article and Find Full Text PDFObservation of magnetic skyrmion lattice in CrMnGe by small-angle neutron scattering.
Sci Rep
January 2025
Helmholtz-Zentrum Berlin für Materialien und Energie, 13109, Berlin, Germany.
Incommensurate magnetic phases in chiral cubic crystals are an established source of topological spin textures such as skyrmion and hedgehog lattices, with potential applications in spintronics and information storage. We report a comprehensive small-angle neutron scattering (SANS) study on the B20-type chiral magnet Cr[Formula: see text]Mn[Formula: see text]Ge, exploring its magnetic phase diagram and confirming the stabilization of a skyrmion lattice under low magnetic fields. Our results reveal a helical ground state with a decreasing pitch from 40 to 35 nm upon cooling, and a skyrmion phase stable in applied magnetic fields of 10-30 mT, and over an unusually wide temperature range for chiral magnets of 6 K ([Formula: see text], [Formula: see text] K).
View Article and Find Full Text PDFPhase formation and phase stability for the homogenous and heterogeneous amorphous metals versus the crystalline phase.
Proc Natl Acad Sci U S A
January 2025
Department of Materials Science and Engineering, Iowa State University, Ames, IA 50011.
From molecular dynamics (MD) simulations of melt-quenching and thermal aging procedures in pure Ag, Cu, Ag-Cu binary alloys, and Cu-Zr binary alloys, we have identified two distinct amorphous phases for a metastable undercooled liquid: the homogeneous L-phase with low shear rigidity and the heterogenous G-phase with much higher shear rigidity and a heterogeneity length scale Λ. Here, we examine two-phase equilibration studies showing that the G-phase melts to form the L-phase above ~1,000 K, which then transforms to form the crystal (X) phase; however, below the melting point of the G-Phase (~990 K), the X- and G-phases do not transform into each other. We suggest the presence of a G-phase is likely responsible for embrittlement often observed in metallic glasses.
View Article and Find Full Text PDFMpemba effect in the relaxation of an active Brownian particle in a trap without metastable states.
J Chem Phys
January 2025
The Institute of Mathematical Sciences, C.I.T. Campus, Taramani, Chennai 600113, India.
We explore the role of activity in the occurrence of the Mpemba effect within a system of an active colloid diffusing in a potential landscape devoid of metastable minimum. The Mpemba effect is characterized by a phenomenon where a hotter system reaches equilibrium quicker than a colder one when both are rapidly cooled to the same low temperature. While a minimal asymmetry in the potential landscape is crucial for observing this effect in passive colloidal systems, the introduction of activity can either amplify or reduce the threshold of this minimal asymmetry, resulting in the activity-induced and suppressed Mpemba effect.
View Article and Find Full Text PDFThermotropic reentrant isotropy and induced smectic antiferroelectricity in the ferroelectric nematic realm: comparing RM734 and DIO.
Soft Matter
January 2025
Department of Physics and Soft Materials Research Center, University of Colorado, Boulder, CO 80309, USA.
The current intense study of ferroelectric nematic liquid crystals was initiated by the observation of the same ferroelectric nematic phase in two independently discovered organic, rod-shaped, mesogenic compounds, RM734 and DIO. We recently reported that the compound RM734 also exhibits a monotropic, low-temperature, apolar phase having reentrant isotropic symmetry (the I phase), the formation of which is facilitated to a remarkable degree by doping with small (below 1%) amounts of the ionic liquid BMIM-PF. Here we report similar phenomenology in DIO, showing that this reentrant isotropic behavior is not only a property of RM734 but is rather a more general, material-independent feature of ferroelectric nematic mesogens.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!