Schematic models of PATP interacting with metal clusters in single-end configurations via the sulfur atom, (a) Au13-PATP, (b) Ag13-PATP, and (c) Cu13-PATP and in double-end configurations via both thiol and amino group, (d) Au13-PATP-Au4, (e) Ag13-PATP-Ag4, (f) Cu13-PATP-Cu4, (g) Au13-PATP-Ag4, (h) Au13-PATP-Cu4, (i) Ag13-PATP-Au4, (j) Ag13-PATP-Cu4, (k) Cu13-PATP-Au4, and (l) Cu13-PATP-Ag4.
Frontier molecular orbitals of aniline (a) and PATP (b). The symmetric representations are assumed under an approximate C2v symmetric point group. The axes were chosen as that the molecule plane is in the yz plane and z is along the C2 axis here. The orbital levels are referred to the vacuum level.
Calculated UV absorption spectrum of the free PATP molecule by TD-DFT with B3LYP/6-311+G(d, p). The absorption line shape was calculated as a sum of Lorentzian bands with a half-bandwidth γ = 1000 cm−1.
Calculated pre-resonance Raman spectra of PATP with different Raman excitation lines. The incident wavelengths are chosen to have energy gaps of 0.1 and 0.2 eV higher and lower with respect to the S1 excited state. The b2 modes in the wavenumber region of 1000 to 1650 cm−1 are marked with short dashed lines.
Schematic diagrams of the photon-driven charge transfer from PATP to metals. (Left) The excitation energy matches the energy gap between the HOMO orbital of adsorbed PATP and Fermi level of metals in the CT process. (Right) The relevant energy states involved in the electronic and vibrational levels in the CT process.
Calculated off-resonance and pre-resonance Raman spectra of (a) Au13-PATP and (b) Ag13-PATP at B3LYP/6-311+G(d, p)/LAN2DZ level. The first two incident wavelengths were chosen to have energy gaps of 0.1 and 0.2 eV with respect to the low-lying CT excited state.
Simulated non-resonance Raman spectra of (a) Au13-PATP-Au4, (b) Ag13-PATP-Ag4, and (c) Cu13-PATP-Cu4 at B3LYP/6-311+G(d, p)/LAN2DZ level. An excitation wavelength of 632.8 nm and a linewidth of 10 cm−1 are used in the simulated spectra.
Simulated non-resonance Raman spectra of PATP trapped into heterojunctions. The NH2 wagging mode and C–N stretching mode are labeled with a red asterisk and a blue dot, respectively.
Simulated pre-resonance Raman spectra of (1) Au13-PATP-Au4, (2) Ag13-PATP-Ag4, (3) Au13-PATP-Ag4, and (4) Ag13-PATP-Au4 with the incident wavelength of 1064 nm.
Vibrational vectors, frequencies (ω, cm−1), and Raman activities (I, Å4/amu) of all the b2 modes in the range of 1000 to 1650 cm−1. The relative Raman intensities defined as a ratio with respect to the a1-type mode at 1088 cm−1 are given in parenthesis.
Calculated vertical transition energies (ΔE) and oscillator strength (f) of the low-lying molecule-to-metal and metal-to-molecule CT transitions and correspond molecular orbitals involved in Au13-PATP, Ag13-PATP, and Cu13-PATP by TD-B3LYP/6-311+G(d, p)/LAN2DZ.
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