ISiCLE: A Quantum Chemistry Pipeline for Establishing in Silico Collision Cross Section Libraries.

High-throughput, comprehensive, and confident identifications of metabolites and other chemicals in biological and environmental samples will revolutionize our understanding of the role these chemically diverse molecules play in biological systems. Despite recent technological advances, metabolomics studies still result in the detection of a disproportionate number of features that cannot be confidently assigned to a chemical structure. This inadequacy is driven by the single most significant limitation in metabolomics, the reliance on reference libraries constructed by analysis of authentic reference materials with limited commercial availability.

Moleculo Long-Read Sequencing Facilitates Assembly and Genomic Binning from Complex Soil Metagenomes.

Soil metagenomics has been touted as the "grand challenge" for metagenomics, as the high microbial diversity and spatial heterogeneity of soils make them unamenable to current assembly platforms. Here, we aimed to improve soil metagenomic sequence assembly by applying the Moleculo synthetic long-read sequencing technology. In total, we obtained 267 Gbp of raw sequence data from a native prairie soil; these data included 109.

Free energies for degradation reactions of 1,2,3-trichloropropane from ab initio electronic structure theory.

Electronic structure methods were used to calculate the gas and aqueous phase reaction energies for reductive dechlorination (i.e., hydrogenolysis), reductive β-elimination, dehydrochlorination, and nucleophilic substitution by OH− of 1,2,3-trichloropropane.

EOMCC, MRPT, and TDDFT studies of charge transfer processes in mixed-valence compounds: application to the spiro molecule.

The proper description of electron transfer (ET) processes in mixed-valence compounds poses a significant challenge for commonly used theoretical approaches. In this paper we analyze the 1(2)A(2) and 2(2)A(2) potential energy surfaces of the Spiro cation (5,5'(4H,4H')-spirobi[cyclopenta[c]pyrrole]2,2',6,6'-tetrahydro cation) which is a frequently used model to study ET processes. We compare and contrast the results obtained with three different methods: multireference perturbation theory, equation-of-motion coupled cluster theory, time-dependent density functional theory.

On the ordering of orbital energies in high-spin ROHF.

The restricted open-shell Hartree-Fock (ROHF) method is a standard tool used by quantum chemists for studying molecules with unpaired electrons. In this work a problem with some implementations of the ROHF method is presented along with an elegant solution. The ground state (2)A(2) potential energy surface of the 5,5'-(4H, 4H')-spirobi[cyclopenta[c]pyrrole]-2,2'6,6'-tetrahydro cation is the molecular test case, which elucidates the underlying problem.

Quantitative molecular thermochemistry based on path integrals.

The calculation of thermochemical data requires accurate molecular energies and heat capacities. Traditional methods rely upon the standard harmonic normal-mode analysis to calculate the vibrational and rotational contributions. We utilize path-integral Monte Carlo for going beyond the harmonic analysis and to calculate the vibrational and rotational contributions to ab initio energies.