Ershov Kirill

PhD student

Master of Science in Physics

Education

Novosibirsk State University

2017 - now

Postgraduate in Physics, Minor: Chemical-Biological Physics

Novosibirsk State University

2015 - 2017

Master of Science in Physics, Minor: Chemical-Biological Physics

Novosibirsk State University

2011 - 2015

Bachelor of Science in Physics, Minor: Chemical-Biological Physics

Publications

Tungsten Isotope-Specific UV-Photodecomposition of W(CO)₆ at 266 nm

The Journal of Physical Chemistry A

UV photodissociation of tungsten hexacarbonyl W(CO)₆ has been studied in the molecular beam conditions using time-of-flight mass spectrometry and velocity map imaging. Irradiation of W(CO)₆ by pulsed laser radiation at 266 nm results in the appearance of singly and doubly charged tungsten ions. The isotope composition of these ions deviates essentially from natural abundance with deviation being pulse energy-dependent. The velocity map images of the tungsten ions indicate proceeding of several, more than two, parallel channels (sequences of the one-photon processes) of photodissociation, giving rise to tungsten atoms. Isotope effect is assigned to appear in a one-photon bound–bound transition in W(CO) intermediate followed by its predissociation. In the model suggested, the final state of this transition is a vibronic state with excited vibrational mode of W–C stretching vibration. This vibrational excitation is responsible for isotopic shift in the location of the final state. The suggested model fits the observed isotopic composition quantitatively.

Decomposition Pathways of Titanium Isopropoxide Ti(OⁱPr)₄: New Insights from UV-Photodissociation Experiments and Quantum Chemical Calculations

The Journal of Physical Chemistry A

The UV-photodissociation at 266 nm of a widely used TiO₂ precursor, titanium tetraisopropoxide (Ti(OⁱPr)₄, TTIP), was studied under molecular-beam conditions. Using the MS-TOF technique, atomic titanium and titanium(II) oxide (TiO) were detected among the most abundant photofragments. Experimental results were rationalized with the aid of quantum chemical calculations (DLPNO–CCSD(T) and DFT). Contrary to the existing data in the literature, the new four-centered acetone-elimination reaction was found to be the primary decomposition process of TTIP. According to computational results, the effective activation barrier of this channel was ∼49 kcal/mol, which was ∼13 kcal/mol lower than that of the competing propylene elimination. The former process, followed by the dissociative loss of an H atom, was a dominating channel of TTIP unimolecular decay. The sequential loss of isopropoxy moieties via these two-step processes was supposed to produce the experimentally observed titanium atoms. In turn, the combination of these reactions with propylene elimination can lead to another detected species, TiO. These results indicate that the existing mechanisms of TTIP thermal and photoinitiated decomposition in the chemical-vapor deposition (CVD) of titanium dioxide should be reconsidered.

Ershov Kirill

PhD student

Education

Novosibirsk State University

Novosibirsk State University

Novosibirsk State University

Publications

Tungsten Isotope-Specific UV-Photodecomposition of W(CO)6 at 266 nm

Decomposition Pathways of Titanium Isopropoxide Ti(OiPr)4: New Insights from UV-Photodissociation Experiments and Quantum Chemical Calculations

Tungsten Isotope-Specific UV-Photodecomposition of W(CO)₆ at 266 nm

Decomposition Pathways of Titanium Isopropoxide Ti(OⁱPr)₄: New Insights from UV-Photodissociation Experiments and Quantum Chemical Calculations