Anisotropic energy absorption from mid-infrared laser pulses in constrained water systems

Heating Anomaly of Cold Interfacial Water under Irradiation of Mid-infrared Pulses

“…The nonlinear water molecule has symmetric and asymmetric OH stretching modes. It is known that the energy absorption intensity of the water molecule in the MIR pulse depends on the transition probability which is proportional to cos 2 θ, where θ is the angle between the direction of the MIR electric field and the transition dipole moment. , Therefore, the smaller the value of average θ is, the greater the absorption intensity will be. The total energy acquisition of the system can be obtained from the integration of the angular distribution over the energy absorption of the individual water molecules.…”

“…appears around 3375 cm −1 , which is the resonant frequency of the asymmetric OH stretching vibration in the potential of the water model TIP3P. 24,35 In principle, there is another resonant peak at the frequency (∼3320 cm −1 ) of the symmetric OH stretching vibration. It is, however, almost fully suppressed with the MIR electric field vertical to the surface since the transition dipole moment of the symmetric OH stretching vibration is mostly parallel to the surface in this case.…”

“…The resonant rupture of the hydrogen bond takes place when the energy acquisition of the water molecule through various excitations in the metastable structures cancels exactly off the hydrogen bonding. Such resonances can be intrigued by the breathing vibration mode of nanochannels, oscillations of the point charge, , far-infrared or mid-infrared (MIR) irradiations, − and so on. At the same time, the resonant energy acquisition can result swiftly in a huge jump of the temperature of the nanosized water. − Recently, we have worked on distinguishing the various heatings of light and heavy nanowater in the far-infrared radiation , and the energy acquisition of water systems in the MIR irradiation .…”

“…Such resonances can be intrigued by the breathing vibration mode of nanochannels, oscillations of the point charge, , far-infrared or mid-infrared (MIR) irradiations, − and so on. At the same time, the resonant energy acquisition can result swiftly in a huge jump of the temperature of the nanosized water. − Recently, we have worked on distinguishing the various heatings of light and heavy nanowater in the far-infrared radiation , and the energy acquisition of water systems in the MIR irradiation . However, a study on the effect of initial temperature on the MIR heating process of the confined 2D water on the interface is still absent.…”

“…21−23 Recently, we have worked on distinguishing the various heatings of light and heavy nanowater in the farinfrared radiation 25,26 and the energy acquisition of water systems in the MIR irradiation. 24 However, a study on the effect of initial temperature on the MIR heating process of the confined 2D water on the interface is still absent. Thus, in this work, we will investigate the dependence of the MIR heating of the interfacial water on the initial temperature and the energy acquisition induced by OH stretching vibrational resonances using molecular dynamics (MD) simulation.…”