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Updated: Jun 12, 2026

Computation of Atmospheric Concentrations of Molecular Clusters from ab initio Thermochemistry
Published on: April 8, 2020
Cooling and collisions of large gas phase molecules
David Patterson1, Edem Tsikata, John M Doyle
1Physics Department, Harvard University, 17 Oxford Street, Cambridge, MA 02138, USA. davepatterson99@gmail.com
Abstract:
Cold and dense samples of naphthalene (C(10)H(8)) are produced using buffer gas cooling in combination with rapid, high flow molecule injection. The observed naphthalene density is n approximately 10(11) cm(-3) over a volume of a few cm(3) at a temperature of 6 K. We observe naphthalene-naphthalene collisions through two-body loss of naphthalene with a loss cross section of sigma(N-N) = 1.4 x 10(-14) cm(2). Analysis is presented that indicates that this combination of techniques will be applicable to many comparably sized molecules. This technique can also be combined with cryogenic beam methods(1) to produce cold, high flux, continuous molecular beams.
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Atoms, molecules, or ions must collide before they can react with each other. Atoms must be close together to form chemical bonds. This premise is the basis for a theory that explains many observations regarding chemical kinetics, including factors affecting reaction rates.
The collision theory is based on the postulates that (i) the reaction rate is proportional to the rate of reactant collisions, (ii) the reacting species collide in an orientation allowing contact between...

