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We establish that matter-wave interference at near-resonant ultraviolet optical gratings can be used to spatially separate individual conformers of complex molecules. Our calculations show that the conformational purity of the prepared beam can be close to 100% and that all molecules remain in their electronic ground state. The proposed technique is independent of the dipole moment and the spin of the molecule and thus paves the way for structure-sensitive experiments with hydrocarbons and biomolecules, such as neurotransmitters and hormones, which evaded conformer-pure isolation so far
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The de Broglie wave nature of matter is a paradigmatic example of fundamental quantum physics and enables precise measurements of forces, fundamental constants and even material properties. However, even though matter-wave interferometry is nowadays routinely realized in many laboratories, this feat has remained an outstanding challenge for the vast class of native polypeptides, the building blocks of life, which are ubiquitous in biology but fragile and difficult to handle. Here, we demonstrate the quantum wave nature of gramicidin, a natural antibiotic composed of 15 amino acids. Femtosecond laser desorption of a thin biomolecular film with intensities up to 1~TW/cm$^2$ transfers these molecules into a cold noble gas jet. Even though the peptides de Broglie wavelength is as tiny as 350~fm, the molecular coherence is delocalized over more than 20 times the molecular size in our all-optical time-domain Talbot-Lau interferometer. We compare the observed interference fringes for two different interference orders with a model that includes both a rigorous treatment of the peptides quantum wave nature as well as a quantum chemical assessment of its optical properties to distinguish our result from classical predictions. The successful realization of quantum optics with this polypeptide as a prototypical biomolecule paves the way for quantum-assisted molecule metrology and in particular the optical spectroscopy of a large class of biologically relevant molecules.
Mass-angle correlation of fission fragments has been understood as manifestation of quasifission. We show that this is not so: the effect can originate from correlation between fusion-fission amplitudes with different total spins signifying matter-wave interference in compound nucleus processes. This resolves the well-known puzzle with the mass-angle correlation in the complete fusion sub-barrier reaction $^{16}$O+$^{238}$U. Our finding is important for more reliable predictions of production cross sections for superheavy elements. Matter-wave interference also produces quantum-classical transition to the time-orientation localization of the coherently rotating dinucleus in quasifission.
The breaking of time reversal symmetry via the spontaneous formation of chiral order is ubiquitous in nature. Here, we present an unambiguous demonstration of this phenomenon for atoms Bose-Einstein condensed in the second Bloch band of an optical lattice. As a key tool we use a matter wave interference technique, which lets us directly observe the phase properties of the superfluid order parameter and allows us to reconstruct the spatial geometry of certain low energy excitations, associated with the formation of domains of different chirality. Our work marks a new era of optical lattices where orbital degrees of freedom play an essential role for the formation of exotic quantum matter, similarly as in electronic systems.
We present the graph-based molecule software Molassembler for building organic and inorganic molecules. Molassembler provides algorithms for the construction of molecules built from any set of elements from the periodic table. In particular, poly-nuclear transition metal complexes and clusters can be considered. Structural information is encoded as a graph. Stereocenter configurations are interpretable from Cartesian coordinates into an abstract index of permutation for an extensible set of polyhedral shapes. Substituents are distinguished through a ranking algorithm. Graph and stereocenter representations are freely modifiable and chiral state is propagated where possible through incurred ranking changes. Conformers are generated with full stereoisomer control by four spatial dimension Distance Geometry with a refinement error function including dihedral terms. Molecules are comparable by an extended graph isomorphism and their representation is canonicalizeable. Molassembler is written in C++ and provides Python bindings.
Conformational isomers or conformers of molecules play a decisive role in chemistry and biology. However, experimental methods to investigate chemical reaction dynamics are typically not conformer-sensitive. Here, we report on a gas-phase megaelectronvolt ultrafast electron diffraction investigation of {alpha}-phellandrene undergoing an electrocyclic ring-opening reaction. We directly image the evolution of a specific set of {alpha}-phellandrene conformers into the product isomer predicted by the Woodward-Hoffmann rules in real space and time. Our experimental results are in quantitative agreement with nonadiabatic quantum molecular dynamics simulations, which provide unprecedented detail of how conformation influences time scale and quantum efficiency of photoinduced ring-opening reactions. Due to the prevalence of large numbers of conformers in organic chemistry, our findings impact our general understanding of reaction dynamics in chemistry and biology.
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