https://hilbeon.com/blog/ Reproducible quantum chemistry for drug discovery — tutorials, DFT walkthroughs, and worked examples from Hilbeon, the easiest quantum chemistry to use. en-us Sun, 05 Jul 2026 10:00:00 GMT Hilbeon static site https://hilbeon.com/blog/reproducible-to-the-last-digit/ How do you trust a quantum-chemistry number? Not by comparing programs. Hilbeon earns it two ways: bit-identical results across machines, and agreement with the bench — caffeine's dipole at 3.56 D, aspirin's carbonyls at 1.20/1.22 A, all reproducible to the last digit. Sun, 05 Jul 2026 10:00:00 GMT https://hilbeon.com/blog/reproducible-to-the-last-digit/ https://hilbeon.com/blog/conformers-your-forcefield-gets-wrong/ A force field calls two conformers a tie; plain DFT picks the wrong one by ~1 kcal/mol. Add London dispersion (D4) and the folded, pi-stacked conformer wins — a 1.5 kcal/mol swing from one physical effect. Why conformer energies need dispersion-aware QM. Sat, 04 Jul 2026 14:00:00 GMT https://hilbeon.com/blog/conformers-your-forcefield-gets-wrong/ https://hilbeon.com/blog/which-tautomer-does-your-assay-see/ A tautomer decides which atoms donate and accept hydrogen bonds — the pharmacophore your target reads. Hilbeon optimizes both forms and adds implicit water: the lactam is stabilized by ~4.7 kcal/mol, swinging 2-pyridone to >99.9% and confirming the 4-quinolone antibiotic core. Sat, 04 Jul 2026 12:00:00 GMT https://hilbeon.com/blog/which-tautomer-does-your-assay-see/ https://hilbeon.com/blog/one-sentence-quantum-chemistry/ We told the Hilbeon assistant to "characterize caffeine" and got back a full quantum portrait — geometry, energies, frontier orbitals, dipole — in a single plain-language thread. The computed dipole (3.56 D) lands right on the measured value. Sat, 04 Jul 2026 10:00:00 GMT https://hilbeon.com/blog/one-sentence-quantum-chemistry/ https://hilbeon.com/blog/desktop-vs-cluster-tco/ A 16-core desktop runs C60 at B3LYP in 215 s and cholesterol DLPNO-MP2 in 247 s. We put its total cost of ownership next to renting the same compute in the cloud — and the box under your desk wins on price and iteration speed. Sat, 04 Jul 2026 09:00:00 GMT https://hilbeon.com/blog/desktop-vs-cluster-tco/ https://hilbeon.com/blog/c60-b3lyp-in-215-seconds/ A job that once wanted 15 GB and a cluster now finishes in 215 s on a desktop — no cluster needed. The how: blocked density evaluation, sparse in-core integrals, and point-group symmetry exploited automatically. Thu, 02 Jul 2026 10:00:00 GMT https://hilbeon.com/blog/c60-b3lyp-in-215-seconds/ https://hilbeon.com/blog/excited-state-gradients/ Absorption is half the story — photochemistry happens where the excited molecule relaxes to. Hilbeon now ships analytic excited-state gradients: optimize S1, run excited-state frequencies, predict emission — validated against finite differences. Wed, 01 Jul 2026 10:00:00 GMT https://hilbeon.com/blog/excited-state-gradients/ https://hilbeon.com/blog/orforglipron-portrait/ Orforglipron is the first oral GLP-1 pill. Hilbeon builds it from its SMILES and converges a real ab-initio wavefunction (1006 basis functions, bit-identical on two machines), then reads its physical frontier orbitals and ionization potential. Sun, 21 Jun 2026 10:00:00 GMT https://hilbeon.com/blog/orforglipron-portrait/ https://hilbeon.com/blog/mof-co2-capture-nobel-2025/ The 2025 Chemistry Nobel went to metal-organic frameworks for capturing CO2. Hilbeon computes the amine binding-site reaction and reproduces the dry-vs-humid carbamic-acid / ammonium-carbamate product shift — water vs vacuum, in one run. Sat, 20 Jun 2026 10:00:00 GMT https://hilbeon.com/blog/mof-co2-capture-nobel-2025/ https://hilbeon.com/blog/photoswitch-azobenzene-uvvis/ Photopharmacology turns a drug on with light, and azobenzene is the workhorse hinge. Hilbeon's TD-DFT reads the trans and cis UV-Vis spectra, the stored energy and the singlet-triplet gap in a single excited-state run. Fri, 19 Jun 2026 10:00:00 GMT https://hilbeon.com/blog/photoswitch-azobenzene-uvvis/ https://hilbeon.com/blog/halogen-bonding-sigma-hole/ A halogen looks negative — yet it donates a bond. Hilbeon maps the sigma-hole: fluorine has none (-18.7), chlorine and bromine grow a positive cap (+18.5, +34.0) — the handle behind halogen bonding in drug design. Wed, 17 Jun 2026 16:00:00 GMT https://hilbeon.com/blog/halogen-bonding-sigma-hole/ https://hilbeon.com/blog/h-bonds-vs-pi-stacking/ Hartree-Fock — and dispersion-less force fields — predict that two aromatic rings REPEL (+2.7 kcal/mol). Hilbeon's HF->MP2->CCSD(T) hierarchy shows why drug binding needs correlated quantum chemistry. Wed, 17 Jun 2026 15:00:00 GMT https://hilbeon.com/blog/h-bonds-vs-pi-stacking/ https://hilbeon.com/blog/amine-basicity/ How protonated is your basic nitrogen at pH 7.4? Hilbeon ranks eight amines by proton affinity and reproduces the experimental order to R^2 = 0.996 — a trustworthy basicity scale for ADMET. Wed, 17 Jun 2026 14:00:00 GMT https://hilbeon.com/blog/amine-basicity/ https://hilbeon.com/blog/drug-ring-electronics/ Electron-rich or electron-poor? Hilbeon maps ten common drug rings on one frontier-orbital ladder — a ready guide to pi-stacking and metabolic-oxidation liability when you pick a scaffold. Wed, 17 Jun 2026 13:00:00 GMT https://hilbeon.com/blog/drug-ring-electronics/ https://hilbeon.com/blog/hammett-substituent-effects/ Medicinal chemists use Hammett sigma to predict how a substituent shifts acidity and reactivity. Hilbeon reproduces the whole scale from first principles — R^2 = 0.94 — so you can score a new substituent before you make it. Wed, 17 Jun 2026 12:00:00 GMT https://hilbeon.com/blog/hammett-substituent-effects/ https://hilbeon.com/blog/carboxylic-acid-vs-tetrazole/ Why does swapping a carboxylic acid for a tetrazole improve permeability? Hilbeon's anion charges show the -1 spread over 4 nitrogens instead of 2 oxygens — the bioisostere's secret. Wed, 17 Jun 2026 11:00:00 GMT https://hilbeon.com/blog/carboxylic-acid-vs-tetrazole/ https://hilbeon.com/blog/tuning-covalent-warheads/ Covalent drugs live and die by their warhead's reactivity. Hilbeon ranks six Michael-acceptor warheads by their LUMO and electrophilicity index — and shows why acrylamide is the 'Goldilocks' choice. Wed, 17 Jun 2026 10:00:00 GMT https://hilbeon.com/blog/tuning-covalent-warheads/ https://hilbeon.com/blog/seeing-hydrogen-bonds-nci/ Salicylic acid hides its polarity behind an intramolecular hydrogen bond — Hilbeon gives a 0.49 D dipole and an NCI surface you can see. The non-covalent interaction analysis maps exactly where the molecule talks to itself, and why that matters for membrane permeability. Wed, 17 Jun 2026 09:00:00 GMT https://hilbeon.com/blog/seeing-hydrogen-bonds-nci/ https://hilbeon.com/blog/metabolic-soft-spots/ Frontier orbitals and electrostatic-potential maps point to likely sites of oxidative metabolism. Paracetamol's HOMO sits right on the phenol ring — exactly where cytochrome P450 oxidizes it to the reactive quinone-imine. Insight, not a single bench number. Mon, 16 Jun 2026 09:00:00 GMT https://hilbeon.com/blog/metabolic-soft-spots/ https://hilbeon.com/blog/predicting-ionization-state-ph-7-4/ Which form of your molecule actually exists in the body? We walk an absolute pKa through a thermodynamic cycle anchored to a reference acid — and find that at blood pH (7.4) more than 99.99% of aspirin is ionized to its carboxylate. Mon, 16 Jun 2026 09:00:00 GMT https://hilbeon.com/blog/predicting-ionization-state-ph-7-4/ https://hilbeon.com/blog/computational-portrait-of-aspirin/ A quantum-chemistry tour of aspirin with Hilbeon: ESP maps, pKa, HOMO reactivity, NCI surfaces, and predicted UV-Vis and 1H NMR — each tied to a real drug-discovery decision. From a single SMILES string to a full quantum portrait in one command. Mon, 16 Jun 2026 09:00:00 GMT https://hilbeon.com/blog/computational-portrait-of-aspirin/