CoastalQuant HCHO Research
Notes on the literature, methods, and findings that inform our formaldehyde measurement research. Each note sets out its sources, scope, and the limits of its conclusions.
6 notes · Newest first
Method note
First published
The focused rule was signed after the first Hessian and before the second. It accepts all 102 internal vibrations; the original rule leaves three unresolved. This reference decision does not confirm the ethanol–coronene pair.
Method note
First published
Targeted scans and separate numerical checks supported a limited energy route for the existing candidate. Its ten softest vibrations remain undetermined. The checks cover specified directions and amplitudes, not a proof of a minimum.
Method note
First published
Updated
· v1.1
Two Hessian calculations and a bound fixed in advance classify 119 of 129 vibrations as clearly positive and none as clearly negative. The ten softest, below about 191 cm⁻¹, remain undetermined, so the candidate is not yet a confirmed minimum.
Method note
First published
Before launch, R02 fixed a one-search scope and rules for recording, stopping, and classifying outcomes. Ethanol moved but stayed within the search region, so the same trajectory continued as required. The final structure remains a candidate requiring review.
Repeatability note
First published
Two separately started ORCA runs differed by 6.7 × 10⁻¹¹ hartree/bohr in their largest force-component difference. The check passed, but it does not establish accuracy or provide a basis for choosing one program over another.
Literature review
Review completed
The reviewed literature supports ethanol interference. It did not establish an observed formaldehyde error above 200% attributable specifically to ethanol.