Self-assembly of (S)-glutamic acid on Ag(100): a combined LT-STM and ab initio investigation.
Self-assembly of organic molecules at metal surfaces is of greatest importance in nanoscience; in fact, it opens new perspectives in the field of molecular electronics and in the study of biocompatible materials. Combining an experimental low-temperature scanning tunneling microscopy investigation with ab initio calculations, we succeeded to describe in detail (S)-glutamic acid adsorption on Ag(100) at T = 350 K. We find that (S)-glutamic acid organizes in a squared structure and, at variance with the majority of cases reported in literature, it adsorbs in the neutral form, 4.6 A above the surface plane. The interaction with the poorly reactive Ag substrate is only due to weak van der Waals forces, while H-bonds between carboxyl groups and the formation of a OCOH-OCOH-OCOH-OCOH cycle at the vertex of the squares are the main responsible for the self-assembly.
Smerieri
M
M
Dipartimento di Fisica dell'Università di Genova, Italy.
Vattuone
L
L
Costa
D
D
Tielens
F
F
Savio
L
L
D000327:Adsorption; D003198:Computer Simulation; D018698:Glutamic Acid / Q000138:chemical synthesis* / Q000737:chemistry; D016252:Microscopy, Scanning Tunneling; D008956:Models, Chemical; D011789:Quantum Theory; D012834:Silver / Q000737:chemistry*; D013237:Stereoisomerism; D013499:Surface Properties; D013696:Temperature
D018698:Glutamic Acid; D012834:Silver