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Estimation of the nucleation barrier in a multicomponent system with intermolecular potential
The formation of a "critical nucleus" prior to phase change is a crucial step for new particle formation (NPF) in the atmosphere. However, the nucleation occurring below ∼1 nm is hard to observe directly. As an effective alternative, theoretical nucleation models have been widely studied....
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| Published in: | Physical chemistry chemical physics : PCCP 2022-06, Vol.24 (23), p.14324-14332 |
|---|---|
| Main Authors: | , , |
| Format: | Article |
| Language: | English |
| Subjects: | |
| Citations: | Items that this one cites Items that cite this one |
| Online Access: | Get full text |
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| Summary: | The formation of a "critical nucleus" prior to phase change is a crucial step for new particle formation (NPF) in the atmosphere. However, the nucleation occurring below ∼1 nm is hard to observe directly. As an effective alternative, theoretical nucleation models have been widely studied. An energy barrier is involved in the nucleation and is the fundamental factor for the nucleation model. Typical atmospheric nucleation agents such as H
2
SO
4
, H
2
O and NH
3
are dipole molecules, whose intermolecular interactions are non-ignorable. Herein, a dipole-dipole potential model is adopted to determine the interaction between molecules instead of the traditional hard sphere model, and graph theory is used to describe the structure of the cluster and the cluster-molecule interaction. The nucleation barriers (Δ
E
b
) of H
2
SO
4
-H
2
SO
4
, H
2
SO
4
-H
2
O, H
2
SO
4
-NH
3
and H
2
SO
4
-H
2
O-NH
3
are derived and compared to each other. In the presence of H
2
O and NH
3
, the Δ
E
b
value is decreased by 17-28% compared to that in the pure H
2
SO
4
nucleation system. NH
3
is identified to be a key factor for ternary nucleation based on an orthogonal test. Atmospheric concentrations of H
2
SO
4
, H
2
O and NH
3
are considered to investigate the influence of [H
2
O + NH
3
]/[H
2
SO
4
] on Δ
E
b
and the related effective collision coefficient (
α
). The
α
value in the ternary nucleation system reaches the range of (2.5-25) × 10
−5
, which is 3-4 orders of magnitude higher than that in the pure H
2
SO
4
system. Due to a significant enhancement of
α
, NH
3
and H
2
O should be focused on in future aerosol particle estimation and control.
The formation of a "critical nucleus" prior to phase change is a crucial step for new particle formation (NPF) in the atmosphere. |
|---|---|
| ISSN: | 1463-9076 1463-9084 |
| DOI: | 10.1039/d2cp00820c |