First accurate experimental study of Mu reactivity from a state-selected reactant in the gas phase: the Mu + H-2{1} reaction rate at 300 K

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68378271%3A_____%2F15%3A00521361" target="_blank" >RIV/68378271:_____/15:00521361 - isvavai.cz</a>

Výsledek na webu

<a href="https://doi.org/10.1088/0953-4075/48/4/045204" target="_blank" >https://doi.org/10.1088/0953-4075/48/4/045204</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1088/0953-4075/48/4/045204" target="_blank" >10.1088/0953-4075/48/4/045204</a>

Jazyk výsledku

angličtina

Název v původním jazyce

First accurate experimental study of Mu reactivity from a state-selected reactant in the gas phase: the Mu + H-2{1} reaction rate at 300 K

Popis výsledku v původním jazyce

This paper reports on the experimental background and methodology leading to recent results on the first accurate measurement of the reaction rate of the muonium (Mu) atom from a state-selected reactant in the gas phase: the Mu + H2 MuH + H reaction at 300 K, and its comparison with rigorous quantum rate theory, Bakule et al (2012 J. Phys. Chem. Lett. 3 2755). Stimulated Raman pumping, induced by 532 nm light from the 2nd harmonic of a Nd:YAG laser, was used to produce H2 in its first vibrational (v = 1) state, H, in a single Raman/reaction cell. A pulsed muon beam (from 'ISIS', at 50 Hz) matched the 25 Hz repetition rate of the laser, allowing data taking in equal 'Laser-On/Laser-Off' modes of operation. The signal to noise was improved by over an order of magnitude in comparison with an earlier proof-of-principle experiment. The success of the present experiment also relied on optimizing the overlap of the laser profile with the extended stopping distribution of the muon beam at 50 bar H2 pressure, in which Monte Carlo simulations played a central role. The rate constant, found from the analysis of three separate measurements, which includes a correction for the loss of concentration due to collisional relaxation with unpumped H2 during the time of each measurement, is = 9.9[(−1.4)(+1.7)] × 10−13 cm3 s−1 at 300 K. This is in good to excellent agreement with rigorous quantum rate calculations on the complete configuration interaction/Born–Huang surface, as reported earlier by Bakule et al, and which are also briefly commented on herein.

Název v anglickém jazyce

First accurate experimental study of Mu reactivity from a state-selected reactant in the gas phase: the Mu + H-2{1} reaction rate at 300 K

Popis výsledku anglicky

This paper reports on the experimental background and methodology leading to recent results on the first accurate measurement of the reaction rate of the muonium (Mu) atom from a state-selected reactant in the gas phase: the Mu + H2 MuH + H reaction at 300 K, and its comparison with rigorous quantum rate theory, Bakule et al (2012 J. Phys. Chem. Lett. 3 2755). Stimulated Raman pumping, induced by 532 nm light from the 2nd harmonic of a Nd:YAG laser, was used to produce H2 in its first vibrational (v = 1) state, H, in a single Raman/reaction cell. A pulsed muon beam (from 'ISIS', at 50 Hz) matched the 25 Hz repetition rate of the laser, allowing data taking in equal 'Laser-On/Laser-Off' modes of operation. The signal to noise was improved by over an order of magnitude in comparison with an earlier proof-of-principle experiment. The success of the present experiment also relied on optimizing the overlap of the laser profile with the extended stopping distribution of the muon beam at 50 bar H2 pressure, in which Monte Carlo simulations played a central role. The rate constant, found from the analysis of three separate measurements, which includes a correction for the loss of concentration due to collisional relaxation with unpumped H2 during the time of each measurement, is = 9.9[(−1.4)(+1.7)] × 10−13 cm3 s−1 at 300 K. This is in good to excellent agreement with rigorous quantum rate calculations on the complete configuration interaction/Born–Huang surface, as reported earlier by Bakule et al, and which are also briefly commented on herein.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10306 - Optics (including laser optics and quantum optics)

Projekt

—

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2015

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Journal of Physics B-Atomic Molecular and Optical Physics

ISSN

0953-4075

e-ISSN

—

Svazek periodika

48

Číslo periodika v rámci svazku

4

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

18

Strana od-do

1-18

Kód UT WoS článku

000349116800008

EID výsledku v databázi Scopus

2-s2.0-84961290043