3.2 Accessing the molecular PAH data

The molecular PAH data is accessed through their associated unique identifier (UID). However, a search-interface is available that allows retrieval of these UIDs through simplified queries. The syntax is the same as used on the NASA Ames PAH IR Spectroscopic Database website.

uids = pahdb.search("c<=20 neutral n=2 neutral")

The molecular PAH data contained in the database XML-files consists of four main parts:

  1. Molecular properties, .e.g, molecular weight, zero point energy, total energy, etc.

  2. Fundamental vibrational transitions

  3. Molecular geometric data

  4. Raw laboratory spectra for a subset of molecules in the experimental database

pahdb = AmesPAHdb()

uids = pahdb.search("c<=20 neutral n=2 neutral")

pahs = pahdb.getspeciesbyuid(uids)

transitions = pahdb.gettransitionsbyuid(uids)

geometry = pahdb.getgeometrybyuid(uids)

laboratory = pahdb.getlaboratorybyuid(uids)

Alternatively, one can access these components through the ‘species’-instance.

pahdb = AmesPAHdb()

pahs = pahdb.getspeciesbyuid(pahdb.search("c<=20 neutral n=2 neutral"))

transitions = pahs.transitions()

geometry = pahs.geometry()

laboratory = pahs.laboratory()