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Ultrafast UV‐pump/soft‐X‐ray‐probe spectroscopy is a subject of great interest since it can provide detailed information about dynamical photochemical processes with ultrafast resolution and atomic specificity. Here, we focus on the photodissociation of ICN in the 1Π1 excited state, with emphasis on the transient response in the soft‐X‐ray spectral region as described by the ab initio spectral lineshape averaged over the nuclear wavepacket probability density. We find that the carbon K‐edge spectral region reveals a rich transient response that provides direct insights into the dynamics of frontier orbitals during the I−CN bond cleavage process. The simulated UV‐pump/soft‐X‐ray‐probe spectra exhibit detailed dynamical information, including a time‐domain signature for coherent vibration associated with the photogenerated CN fragment., Ultrafast UV‐pump/soft‐X‐ray‐probe spectroscopy provides detailed information about dynamical photochemical processes with ultrafast resolution and atomic specificity. Here, the photodissociation of ICN in the 1Π1 excited state is studied. The carbon K‐edge spectral region reveals a rich transient response that provides direct insights into the dynamics of frontier orbitals during the I−CN bond cleavage process.

Aligned protein α-helix dipoles have been implicated in protein function and structure. The recent breakthroughs in high-resolution electron microscopy (EM) of macromolecules makes it possible to explore fundamental aspects of structural biology at the detailed molecular level. The electrostatic potential (ESP) generated by aligned protein α-helix dipole should be observable in high-resolution EM maps despite the fact that the effect may be partially screened by induced electric fields. Here, we show that aligned backbone dipoles in protein α-helices account for long-range features in the protein ESP functions. Our results are consistent with experimental EM maps and density functional theory calculations, including direct Fourier summation for proper calculation of the ESP due to the nonlocal nature of the ESP function from aligned dipoles and other partial atomic charges.