Plasmon-driven sub-picosecond breathing of metal nanoparticles

BONAFÉ, FRANCO P.; ARADI, BÁLINT; GUAN, MENGXUE; DOUGLAS-GALLARDO, OSCAR A.; LIAN, CHAO; MENG, SHENG; FRAUENHEIM, THOMAS; CRISTIÁN G. SÁNCHEZ

Nanoscale

Royal Society of Chemistry

Año: 2017 vol. 9 p. 12391 - 12397

2040-3364

We present the first real-time atomistic simulation on the quantum dynamics of icosahedral silver nanoparticles under strong laser pulses, using time dependent density functional theory (TDDFT) molecular dynamics. We identify the emergence of sub-picosecond breathing-like radial oscillations starting immediately after laser pulse excitation, with increasing amplitude as the field intensity increases. The ultrafast dynamic response of nanoparticles to laser excitation points to a new mechanism other than equilibrium electron-phonon scattering previously assumed, which takes a much longer timescale. A sharp weakening of all bonds during laser excitation is observed, thanks to plasmon damping into excited electrons in anti-bonding states. This sudden weakening of bonds leads to a uniform expansion of the nanoparticles and launches coherent breathing oscillations.