Photodissociation of H$_2$ on Ag and Au Nanoparticles: Effect of Size, and Plasmon versus Inter-Band Transitions on Threshold Intensities for Dissociation
This paper provides new insights concerning the simulation of plasmon driven chemical reactions using real-time TDDFT based on the tight-binding electronic structure code DFTB+, with applications to the dissociation of H$_2$ on octahedral silver and gold nanoparticles with 19-489 atoms. A new component of these calculations involves sampling a 300 K canonical ensemble to determine the distribution of possible outcomes of the calculations, and with this approach we are able to determine the threshold for dissociation as a function of laser intensity, wavelength, and nanocluster size. We show that the threshold intensity varies as an inverse power of nanocluster size, which makes it possible to extrapolate the results to sizes that are more typical of experimental studies. The intensities obtained from this extrapolation are around a factor of 100 above powers used in the pulsed experiments. This is a closer comparison of theory and experiment than has been obtained in previous real-time simulations, and the remaining discrepancy can be understood in terms of electromagnetic hot spots that are associated with cluster formation. We also compare the influence of plasmon excitation versus inter-band excitation on reaction thresholds, revealing that for silver clusters plasmon excitation leads to lower thresholds, but for gold clusters, inter-band excitation is more effective. Our study also includes an analysis of charge transfer to and from the H$_2$ molecule, and a determination of orbital populations during and after the pulse, showing the correlation between metal excitations and the location of the antibonding level of H$_2$.
Observation of Above-Threshold Dissociation of Na$_2^+$ in Intense Laser Fields
本文报道了多电子分子Na $_2^+$的阈上解离现象。这个过程是由于在一个场修饰的分子连续谱的连续-连续跃迁。已检测到三个具有不同动能释放模式的良好分辨的碎片化通道，其中两个与通过光诱导电位的普通光解离成Na（3s）+ Na $^+$和Na（3 p）+ Na $^+$相关，一个与连续-连续跃迁和高于阈值的解离成Na（3 p）+ Na $^+$相关。我们发现，当我们穿着这个分子与一个字段的强度为~3 × 10 $^{12}$ W/cm $^2$，高于阈值的解离优于其他过程，如场电离，然后库仑爆炸。
Intensities of KCs $E(4)^1Σ^+\to (a^3Σ^+,X^1Σ^+)$ band system up to dissociation threshold: an interplay between spin-orbit, hyperfine and rovibronic coupling effects
Photodissociation dynamics in the first absorption band of pyrrole: I. Molecular Hamiltonian and the Herzberg-Teller absorption spectrum for the $1^1A_2(πσ^*) \leftarrow \tilde{X}^1A_1(ππ)$ transition
Energy-dependent normal and unusually large inverse chlorine kinetic isotope effects of simple chlorohydrocarbons in collision-induced dissociation by gas chromatography-tandem mass spectrometry
Theory on polarization-averaged core-level molecular-frame photoelectron angular distributions: II. Extracting the X-ray induced fragmentation dynamics of carbon monoxide dication from forward and backward intensities
