What does it take to stabilize a naphthalene anion?

Area of Science:

• Physical Chemistry
• Chemical Physics
• Materials Science

Background:

• Naphthalene clusters are studied for their unique electronic properties.
• Understanding electron attachment is crucial for molecular electronics and materials science.
• Previous studies have explored electron interactions with smaller aromatic molecules.

Purpose of the Study:

• To investigate the attachment of slow electrons to naphthalene clusters.
• To determine the formation mechanisms and stability of naphthalene cluster anions.
• To analyze the role of rare-gas atoms in stabilizing these anions.

Main Methods:

• Crossed beam experiment with supersonic expansion of naphthalene.
• Generation of neat and mixed naphthalene-rare gas clusters (He, Ne, Ar, Kr).
• Mass spectrometry and measurement of electron energy-dependent ion yields.

Main Results:

• The naphthalene dimer anion ((Np)2-) is not formed directly but via Ar evaporation from mixed clusters.
• Larger naphthalene cluster anions (n>3) decay through naphthalene unit evaporation.
• A self-scavenging process occurs around 6 eV, involving electronic excitation and trapping.
• Mixed clusters with rare gases efficiently stabilize transient negative ions through atom evaporation.

Conclusions:

• Naphthalene cluster anion formation is highly dependent on cluster size and composition.
• Rare-gas atoms play a critical role in stabilizing naphthalene cluster anions.
• Electron attachment dynamics reveal complex decay pathways including evaporation and self-scavenging.