PAH IR Spectroscopic Database Archives

Diagnostic band ratio diagrams extracted from the PAH diagnostic grids (Figure 4), illustrating the influence of varying aliphatic content (0%, 33.3%, 50%, and 100%) at five fixed ionization fractions (Neutral, N67C33, N50C50, N33C67, and Cation). Each panel presents data points representing individual PAH species or mixtures color-coded by their number of carbon atoms (Nc). Linear fits (solid and dashed lines) connect points within each ionization fraction to quantify trends in diagnostic ratios with increasing aliphatic content. The bottom-right panel summarizes these trends by showing the slope distribution histogram of the linear fits across different ionization states, highlighting the systematic increase in slope with aliphatic fraction for all cases except the fully ionized state. -- astro-ph.GA

Astrochemistry, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Biophysics, Biosignatures & Paleobiology, Imaging & Spectroscopy, Interstellar, Status Report

The Influence of Aliphatic Components on the Aromatic Emission Characteristics of Polycyclic Aromatic Hydrocarbons

by Keith CowingMay 14, 2026May 14, 2026

Intensity ratios of aromatic emission features are widely used to diagnose the size and ionization state of polycyclic aromatic hydrocarbons (PAHs) in astronomical environments.

PAH IR Spectroscopic Database

The Influence of Aliphatic Components on the Aromatic Emission Characteristics of Polycyclic Aromatic Hydrocarbons

Why Europa’s Hidden Ocean May Be More Difficult To Reach Than Scientists Thought

Pinpointing Where Cells First Begin Copying DNA

Experimental Measurements of Benzene Ice Critical Saturation Ratios on Titan Tholins and Impact on the Microphysical Modeling of Titan’s South Polar Benzene Cloud

From Mars to Minas: Research Reclassifies Organisms That Thrive In Highly Saline Environments

Could Alien Signals Be Hiding On A Different Radio Channel?