Solvent Polarity Dependent Ultrafast Relaxation Kinetics of ADS800AT Dye.

This work investigated the photoexcitation and relaxation kinetics of the ADS800AT dye dissolved in different solvents using transient absorption spectroscopy (TAS) with a white-light continuum probe. The dye was dissolved in various solvents, including dichloromethane (DCM), 1,2-dichlorobenzene (DCB), ethanol, and methanol, to study their impact on the dye's characteristics. The linear absorption peak varied from 835 to 809 nm, depending on the polarity of the solvent, and the pump wavelength for TAS was chosen accordingly.

Broadband absorption of nanostructured stainless steel surface fabricated by nanosecond laser irradiation.

Highly efficient broadband absorbing surfaces covering the UV, visible and near-IR regions are of great importance for low-light imaging devices, optical devices and optoelectronic devices. In this work, we demonstrate the fabrication of remarkably efficient absorbing surfaces due to the formation of nanoflower-like cavity structures on a stainless steel (SS304) surface, along with micropatterning in a hierarchical fashion. The fabrication process is carried out using noncontact, programmable, single-step laser irradiation by an inexpensive and robust 532 nm nanosecond laser.

C-D modes of deuterated side chain of leucine as structural reporters via dual-frequency two-dimensional infrared spectroscopy.

Perdeuteration of the side chains of amino acids such as leucine results in appearance of reasonably strong absorption peaks around 2050-2220 cm(-1) that belong to the CD stretching modes and exhibit extinction coefficients of up to 120 M(-1) cm(-1). The properties of the CD stretching transitions in leucine-d(10) as structural labels are studied via the methods of two-dimensional infrared (2DIR) spectroscopy. The cross peaks caused by interactions of the CD stretching modes with amide I (Am-I), CO, and amide II (Am-II) modes are obtained by the dual-frequency 2DIR method.

Bond connectivity measured via relaxation-assisted two-dimensional infrared spectroscopy.

The relaxation-assisted two-dimensional infrared (RA 2DIR) method is a novel technique for probing structures of molecules, which relies on vibrational energy transport in molecules. In this article we demonstrate the ability of RA 2DIR to detect the bond connectivity patterns in molecules using two parameters, a characteristic intermode energy transport time (arrival time) and a cross-peak amplification coefficient. A correlation of the arrival time with the distance between the modes is demonstrated.

A relaxation-assisted 2D IR spectroscopy method.

A method of two-dimensional infrared (2D IR) spectroscopy called relaxation-assisted 2D IR (RA 2DIR) is proposed that utilizes vibrational energy relaxation transport in molecules to enhance cross-peak amplitudes. This method substantially increases the range of distances accessible by 2D IR and is capable of identifying long-range connectivity patterns in molecules. RA 2DIR is illustrated in interactions among CN and CO modes in 3-cyanocoumarin and 4-acetylbenzonitrile, where the distances between the CN and CO groups are approximately 3.

Dual-frequency 2D IR on interaction of weak and strong IR modes.

Dual-frequency 2D IR heterodyne photon-echo spectroscopy of C[triple bond]N and C=O stretching vibrational modes in 2-cyanocoumarin is reported. We have shown that the interaction among these modes provides convenient and useful structural constraints for molecules. Implementation of two pulse sequences, 4, 4, and 6 microm and 6, 6, and 4 microm, allowed the clear determination of contributions caused by vibrational relaxation.