Laser photochemical ablation of CdWO4 studied with the time-of-flight mass spectrometric technique

Abstract

Pulsed laser ablation of CdWO4 at 266 nm is studied with a quadrupole mass spectrometric (QMS) time-of-flight method. Ablation threshold, energy distribution, and angular distribution of the ablated species as well as nonlinearity of the ablated species mass intensity are elucidated as a function of laser fluence. Ablated species of O+2, Cd+, Cd2+, W+, and WO+ translate with energies strongly depending on the fragment mass, meaning that they are confined in a space with the same velocity distribution. Ablated species detected with the QMS filament off show a Gaussian distribution for their translation energy, which is interpreted by the Franck–Condon electron excitation mechanism. A simple model is proposed based on a photochemical bond breaking to explain the observed threshold and nonlinearity of the ablated species. Nonlinearity can be explained by photofragmentation of CdWO4 cluster ions and the successively occurring volume expansion. The latter will be the main cause for the desorption of ion species by ablation and supports the narrow angular spreading of the ablated species.

Synthesis and Surface Thermodynamic Functions of CaMoO4 Nanocakes

“…Calcium molybdate (CaMoO4) with scheelite type structure has attracted broad interest due to its interesting potential applications in various realms such as photoluminescence [14,15], scintillation detectors [16], optical fibers [17], catalysts [18], microwave applications [19], energy storage [20], etc. As we know, nanostructured materials possess many unique and interesting properties which differ from their bulk versions.…”

Controllable synthesis of CdWO₄ nanorods and nanowires via a surfactant-free hydrothermal method

“…Appropriate amounts of Na 2 WO 4 and CdCl 2 were dissolved in distilled water to form aqueous solutions, separately; and then mixed together with strongly magnetic stirring at room temperature. The suspension solution was transferred into the stainless-steel autoclave for hydrothermal treatment.…”

“…Cadmium tungstate (CdWO 4 ) is deemed to be an important material due to its chemical and optical properties. 4), 5) Various techniques have been developed to synthesize CdWO 4 crystals, such as solid-state metathetic reaction for CdWO 4 particles, 6) co-precipitation method for nanoparticles, 7) and molten salt route for nanorods. 8) Hydrothermal method is considered as an effective and convenient synthetic process.…”

Silver nanoparticles and silver molybdate nanowires complex for surface-enhanced Raman scattering substrate

“…Molybdenum is a kind of important inorganic materials and can be widely used in the photoluminescence [1], microwave [2], fiber optic [3], scintillator [4], humidity sensors [5], magnetic [6], catalyst [7], and other aspects [8]. The previously reported synthetic methods of molybdate, mostly had been performed at high temperature or required other harsh conditions, such as at 1000°C under solid state metal exchange reaction [9], or sol-gel process [10].…”