Browsing Department of Chemistry Faculty Publications by Title
Now showing items 49-68 of 86
-
Near Infrared Absorption Detection in Picolitre Liquid Volumes Using Fiber Loop Ring-Down Detection
(2016-03-07)Cavity ring-down spectroscopy is performed using a single-mode fibre loop as an optical cavity. The loop contains absorption cells for either liquids or gases, as well as an erbium-doped fibre amplifier. The fibre amplifier ... -
Neural Networks vs Gaussian Process Regression for Representing Potential Energy Surfaces: a Comparative Study of Fit Quality and Vibrational Spectrum Accuracy
(2018)For molecules with more than three atoms, it is difficult to fit or interpolate a potential energy surface (PES) from a small number of (usually ab initio) energies at points. Many methods have been proposed in recent ... -
A New Collocation-Based Multi-Configuration Time-Dependent Hartree (MCTDH) Approach for Solving the Schrödinger Equation With a General Potential Energy Surface
(2018-01-08)We present a new collocation-based multi-configuration time-dependent Hartree (MCTDH) approach for solving the Schrödinger equation required to compute (ro-)vibrational spectra, photodissociation cross sections, reaction ... -
Optical Fiber Sensing Based on Reflection Laser Spectroscopy
(2016-03-22)An overview on high-resolution and fast interrogation of optical-fiber sensors relying on laser reflection spectroscopy is given. Fiber Bragg-gratings (FBGs) and FBG resonators built in fibers of different types are used ... -
Perspective: Computing (ro-)Vibrational Spectra of Molecules With More Than Four Atoms
(2017-03-31)In this perspective, I review methods for computing (ro-)vibrational energy levels and wavefunctions of molecules with more than four atoms. I identify three problems one confronts (1) reducing the size of the basis; (2) ... -
Phase-Shift Cavity Ring-Down Spectroscopy on a Microsphere Resonator by Rayleigh Backscattering
(2016-03-04)The optical ring-down time in a silica microsphere resonator is measured using phase-shift cavity ring-down spectroscopy. When detecting Rayleigh backscattered light that is coupled into the input waveguide it is found ... -
Photoelectron Imaging Following 2 þ 1 Multiphoton Excitation of HBr
(2016-03-29)The photodissociation and photoionization dynamics of HBr via low-n Rydberg and ion-pair states was studied by using 2 + 1 REMPI spectroscopy and velocity map imaging of photoelectrons. Two-photon excitation at about 9.4–10 ... -
Photonic Guitar Pick-up: Fiber Strain Sensors Find Applications in Music Recording
(2016-03-07)In this report we give a summary of our work on the development of low-noise fiber-optic strain sensors. Three types of strain sensors were developed and were tested by attaching them to the bodies of acoustic guitars. The ... -
Proton Formation in 2+1 Resonance Enhanced Multiphoton Excitation of HCl and HBr via „=0… Rydberg and Ion-Pair States
(2016-03-22)Molecular beam cooled HCl was state selected by two-photon excitation of the V (1) summation operator(0(+)) [v=9,11-13,15], E (1) summation operator(0(+)) [v=0], and g (3) summation operator(-)(0(+)) [v=0] states through ... -
A Pruned Collocation-Based Multiconfiguration Time-Dependent Hartree Approach Using a Smolyak Grid for Solving the Schrödinger Equation with a General Potential Energy Surface
(2019)Standard multiconfiguration time-dependent Hartree (MCTDH) calculations use a direct product basis and rely on the potential being a sum of products (SOPs). The size of the direct product MCTDH basis scales exponentially ... -
Purification and Kinetic Characterization of the Essential Condensation Enzymes Involved in Prodiginine and Tambjamine Biosynthesis
(Wiley, 2019)Prodiginines and tambjamines are related families of bioactive alkaloid natural products with pharmaceutical potential. Both compound families result from a convergent biosynthetic pathway ending in the condensation of a ... -
Quantification of Different Water Species in Acetone using a NIR-Triple-Wavelength Fiber Laser
(2016-02-25)A fiber laser using a thulium-doped ZBLAN gain medium was used to generate laser radiation simultaneously at 1461, 1505 and 1874 nm, with > 5 mW output power at each of the wavelengths. The laser was used to quantify the ... -
Recording the Sound of Musical Instruments with FBGs: the Photonic Pickup
(2016-03-18)Fiber Bragg gratings (FBGs) have previously found many applications as strain and vibration sensors. Here we demonstrate that they may also be employed as pickups for musical instruments and, specifically, for acoustic ... -
Reducing the Cost of Using Collocation to Compute Vibrational Energy Levels: Results for CH2NH
(2017-07-31)In this paper, we improve the collocation method for computing vibrational spectra that was presented in the work of Avila and Carrington, Jr. [J. Chem. Phys. 143, 214108 (2015)]. Known quadrature and collocation methods ... -
Redundant Coordinates in Quantum Mechanics
(2018)We present a kinetic energy operator and inner product that can be used to solve the Schroedinger equation in redundant coordinates. The goal is to develop equations and a computational procedure that can be used with N ... -
Refractive Index Sensor Based On An Abrupt Taper Michelson Interferometer In a Single-Mode Fiber
(2016-03-21)A simple refractive index sensor based on a Michelson interferometer in a single-mode fiber is constructed and demonstrated. The sensor consists of a single symmetrically abrupt taper region in a short piece of single-mode ... -
Ring-Down Absorption Spectroscopy for Analytical Microdevices
(2016-03-22)Ring-down absorption spectroscopy is an emerging ‘‘label-free’’ detection method for analytical microdevices, such as micrototal analysis systems (l-TAS). Developed from the related gas-phase cavity ring-down absorption ... -
Single-Mode Fiber Refractive Index Sensor Based on Core-Offset Attenuators
(2016-03-18)Mach-Zehnder and Michelson interferometers using core-offset attenuators were demonstrated. As the relative offset direction of the two attenuators in the Mach-Zehnder interferometer can significantly affect the extinction ... -
Spatial Coating Inhomogeneity of Highly Reflective Mirrors Determined by Cavity Ringdown Measurements
(2016-03-02)The inhomogeneity of high-reflectivity mirror coatings is a potential error source in the application of the cavity ringdown technique. Here, the ringdown times for different transverse modes were recorded. Together with ... -
State-Selective Photodissociation Dynamics of Formaldehyde: Near Threshold Studies of the H+HCO Product Channel
(2016-03-22)The laser-induced photodissociation of formaldehyde in the wavelength range 309<λ<330nm 309<λ<330nm has been investigated using H (Rydberg) atom photofragment translational spectroscopy. Photolysis wavelengths corresponding ...