We demonstrate a method for performing nonlinear microspectroscopy that provides an intuitive and unified description of the various signal contributions, and allows the direct extraction of the vibrational response. Three optical fields create a pair of Stokes Raman pathways that interfere in the same vibrational state. Frequency modulating one of the fields leads to amplitude modulations on a...

UV-pump/broadband-mid-IR-probe transient absorption (TA) experiments and ab initio quantum mechanical (QM) calculations were used to investigate the photophysics in heavy water of the neutral and acid forms of guanosine 5'-monophosphate (GMP and GMPD(+), respectively). Excited GMP undergoes ultrafast internal conversion (IC) and returns to the electronic ground state in less than one picosecond...

Vibrational resonance manifests itself in certain nonlinear systems that are subject to the action of a biharmonic force with very different frequencies. A proper frequency and/or amplitude of the high-frequency harmonic signal can lead to a resonantly enhanced response of the system with respect to the low frequency signal. In the present study we extent the concept of vibrational resonance to...

First-principles theoretical methods were used to investigate the vibrational properties of pentaerythritol tetranitrate (PETN) under hydrostatic compression up to 4 GPa. Bond lengths and bond angles for the PETN molecules and the pressurevolume relation for the crystal under high pressure were calculated and compared with previous calculations and with experimental results. Based on the calcul...

The results of analytical study of vibrational resonance (VR) occurring in overdamped bistable system driven by two periodic signals with very different frequencies are presented. Approximate solutions for responses at the low-frequency as a function of the amplitude, and the frequency of the additional high frequency modulation which describe well the main features of vibrational resonance are...

Vibrational frequency shifts of H2 in clathrate hydrates are important to understand the properties and elucidate details of the clathrate structure. Experimental spectra of H2 in clathrate hydrates have been measured for different clathrate compositions, temperatures, and pressures. In order to establish reliable relationships between the clathrate structure, dynamics, and observed frequencies...

We report the occurrence of vibrational resonance in excitable systems. Namely, we show that an optimal amplitude of the high-frequency driving enhances the response of an excitable system to a low-frequency signal. The phenomenon is confirmed in an excitable electronic circuit and in the FitzHugh–Nagumo model. In this last case we also analyze the influence of additive noise and the interplay ...

Electronic and vibrational correlations report on the dynamics and structure of molecular species, yet revealing these correlations experimentally has proved extremely challenging. Here, we demonstrate a method that probes correlations between states within the vibrational and electronic manifold with quantum coherence selectivity. Specifically, we measure a fully coherent four-dimensional spec...

Deprotonated thymine can exist in two different forms, depending on which of its two N sites is deprotonated: N1[T-H]- or N3[T-H]-. Here we report a photodetachment study of the N1[T-H]- isomer cooled in a cryogenic ion trap and the observation of an excited dipole-bound state. Eighteen vibrational levels of the dipole-bound state are observed, and its vibrational ground state is found to be 23...

In the present research, vibrational behavior of anisotropic protein microtubules (MTs) immersed in cytosol via Cooper–Naghdi shell model is investigated. MTs are hollow cylindrical structures in the eukaryotic cytoskeleton which surrounded by filament network. The temperature effect on vibration frequency is also taken into account by assuming temperature-dependent material properties for MTs....