The Laser Synthesis of Linear Polyynes: The Particle in a Box Revisited

Cryogenic Photochemical Synthesis and Electronic Spectroscopy of Cyanotetracetylene

“…a Ground state electronic configuration: Vibrational frequencies characterizing ܺ ෨ , ‫ܤ‬ ෨ , and ‫ܧ‬ ෨ states are listed in In the homologous series of polyynes, UV absorption wavelengths have been shown to change almost linearly with the size of the chain. 68,69 This can be simplistically rationalized by considering a classical particle-in-a-box model, where a valence electron (a 'particle') is delocalized in a system ('box') of conjugated bonds. 68 Prior to the present study, phosphorescence of HC 7 N, 36 HC 5 N, 35 and C 3 Nanion 70 has been observed (HC 3 N, isoelectronic with C 3 N -, does not phosphoresce), and the wavelengths of the corresponding vibrationless ܽ − ܺ ෨ emission origins were found to be linearly correlated with the length of the carbonnitrogen chain.…”

“…68,69 This can be simplistically rationalized by considering a classical particle-in-a-box model, where a valence electron (a 'particle') is delocalized in a system ('box') of conjugated bonds. 68 Prior to the present study, phosphorescence of HC 7 N, 36 HC 5 N, 35 and C 3 Nanion 70 has been observed (HC 3 N, isoelectronic with C 3 N -, does not phosphoresce), and the wavelengths of the corresponding vibrationless ܽ − ܺ ෨ emission origins were found to be linearly correlated with the length of the carbonnitrogen chain. 36 Extrapolation of this empirical trend places the origin of HC 9 N phosphorescence near 588 nm or 2.11 eV.…”

Introductory Chemistry Laboratory: Quantum Mechanics and Color

“…These materials produce visually similar colors through different microscopic processes. − Exploring the origins of color in these three types of materials offers a unique opportunity to design a wet chemistry laboratory that not only is refreshing and engaging to stimulate a student’s interest in learning and curiosity in science but also helps them to have a tangible understanding of rather dry complex quantum mechanics principles. There have been several upper-level undergraduate physical chemistry laboratories emphasizing the particle-in-a-box to model the energy levels in conjugated organic dye molecules. − The color of transition metal complexes in terms of d–d electronic transitions between energy levels split by the ligand field has been the subject of theoretical and experimental treatments. ,, However, no laboratories are available for introductory chemistry students connecting color observed in transition metal complexes or gemstones to the nondegeneracy of d orbitals, a concept which may be covered in an introductory curriculum. Nanoparticle synthesis experiments have been previously performed in undergraduate laboratories. − Frank and Métraux have both published original protocols , for the synthesis of silver nanoprism particles with different sizes.…”

Resonant Effects in SERS Spectra of Linear Carbon Chains

“…However, under other conditions, the chain length is limited. For instance, synthesis by arc‐discharge and by femtosecond laser ablation in various organic solvents provides the LCC with length up to 40 carbon atoms, with most probable length of 8–12 atoms. The finite size polyynic chains, similar to quantum box, have the electronic and phonon energy levels, determined by their length.…”