Investigation of the position of the radical in z₃-ions resulting from electron transfer dissociation using infrared ion spectroscopy

Abstract

The molecular structures of six open-shell z3-ions resulting from electron transfer dissociation mass spectrometry (ETD MS) were investigated using infrared ion spectroscopy in combination with density functional theory and molecular mechanics/molecular dynamics calculations.

Reference-standard free metabolite identification using infrared ion spectroscopy

“…The intensity values of the computational spectra are evaluated at the same wavenumber points as the experimental spectrum, in order to ensure a common x-axis. The above equation is slightly modified to make the similarity S less sensitive to intensity deviations and thus more sensitive to frequency overlap [50]. This is achieved by scaling both the experimental and computational spectra to 1 and then taking the logarithm:…”

Sodium cationization can disrupt the intramolecular hydrogen bond that mediates the sunscreen activity of oxybenzone

“…This similarity measure has been shown to be a successful tool for evaluating molecular-based systematic relationships, [39][40][41] including IRMPD spectral fits. 42 Fit similarity is assessed as the cosine of the angle y between two spectral vectors A and B, which is calculated as the dot product of these vectors divided by the product of their Euclidian norms, according to:…”

“…To confirm the qualitative assignment of the experimental M + Á OB IRMPD spectra presented in the last section, spectral matching was performed. 42 Table 2 lists the spectral matching scores obtained. Further details of how the matching scores were obtained are available in Section S5 of the ESI.…”

Unravelling the configuration of transient ortho-quinone methides by combining microfluidics with gas phase vibrational spectroscopy

“…To obtain an objective score for the agreement between experimental and computed spectra, the cosine similarity score 22 was employed. The score expresses the similarity S between two spectra A and B by their normalized Euclidean dot products according to:…”