Molecular dynamics with constrained nuclear electronic orbital density functional theory: Accurate vibrational spectra from efficient incorporation of nuclear quantum effects

Nuclear quantum effects play a crucial role in many chemical and biological systems involving hydrogen atoms yet are difficult to include in practical molecular simulations. In this Letter, we combine our recently developed methods of constrained nuclear-electronic orbital density functional theory (cNEO-DFT) and constrained minimized energy surface molecular dynamics (CMES-MD) to create a new method for accurately and efficiently describing nuclear quantum effects in molecular simulations. Using this new method, dubbed cNEO-MD, the vibrational spectra of a set of small molecules are calculated and compared with those from conventional ab initio molecular dynamics (AIMD) as well as from experiments. With the same formal scaling, cNEO-MD greatly outperforms AIMD in describing the vibrational modes with significant hydrogen motion characters, demonstrating the promise of cNEO-MD for simulating chemical and biological systems with significant nuclear quantum effects.

Intra-orbital Wooden Foreign Body

Intra orbital wooden foreign body (IOWFB) injuries are common cause of visual loss. The diagnosis is difficult, it may be missed from the imaging perspective. A case series is reviewed between 2013 and 2017. Of the 4 cases, 3 were caused by tree branch and 1 by bamboo. The postoperative vision was improved in 75%, but not in 25% subjects due to optic nerve damage. To be strongly suspected intra orbital wooden foreign body when the intra orbital density below of the surrounding intra orbital fat on CT. All the intra orbital wooden foreign body were removed successfully without any complications.