9 research outputs found
Experimental verification of minima in excited long-range Rydberg states of Rb_2
Recent theoretical studies with alkali atoms A excited to high
Rydberg states predicted the existence of ultra long-range molecular bound
states. Such excited dimers have large electric dipole moments which, in
combination with their long radiative lifetimes, make them excellent candidates
for manipulation in applications. This letter reports on experimental
investigations of the self-broadening of Rb principal series lines, which
revealed multiple satellites in the line wings. The positions of the satellites
agree quantitatively with theoretically-predicted minima in the excited
long-range Rydberg states of Rb.Comment: 3 figures, 5 pages in two-column forma
Atmospheric Helium Capillary Dielectric Barrier Discharge for Soft Ionization: Determination of Atom Number Densities in the Lowest Excited and Metastable States
The populations of the lowest excited
helium states 2s <sup>3</sup>S<sub>1</sub>, 2s <sup>1</sup>S, 2p <sup>3</sup>P<sup>0</sup><sub>J</sub>, and 2p <sup>1</sup>P<sup>0</sup> created in an atmospheric
helium capillary dielectric barrier discharge were determined by means
of optical emission spectroscopy. The emitted intensities of 388,
501, 587, and 667 nm lines were measured side-on and end-on with respect
to the discharge axis. The comparison of optically thin side-on spectra
with end-on spectra, which exhibited the absorption effects in the
line kernels, enabled the determination of the average values of the
number densities <i>n</i><sub>1</sub> in the considered
He states along the plasma length <i>L</i>. The field of
the theoretical profiles for a series of the <i>n</i><sub>1</sub><i>L</i> parameters pertinent to the experimental
conditions was calculated for each line. By introducing the experimental
data into the field of calculated curves, <i>n</i><sub>1</sub><i>L</i> corresponding to the particular state could be
obtained. The measurements of the emission profiles were done as a
function of the discharge voltage in the range covering homogeneous
as well as filamentary DBD operation mode. Due to nonuniformity of
the excited atom density distribution along the plasma, the values
of <i>n</i><sub>1</sub> could be obtained only in the homogeneous
operation mode where the nonuniformity was small. The following maximum
values were found for the number densities in the investigated states: <i>n</i><sub>1</sub><sup>av</sup> (2s <sup>3</sup>S<sub>1</sub>) = (2.9 ± 1.1) × 10<sup>13</sup> cm<sup>–3</sup>, <i>n</i><sub>1</sub><sup>av</sup> (2s <sup>1</sup>S) = (1.4 ±
0.5) × 10<sup>13</sup> cm<sup>–3</sup>, <i>n</i><sub>1</sub><sup>av</sup> (2p <sup>3</sup>P<sup>0</sup><sub>J</sub>) = (1.1 ± 0.4) × 10<sup>13</sup> cm<sup>–3</sup>, <i>n</i><sub>1</sub><sup>av</sup> (2p <sup>1</sup>P<sup>0</sup>) = (4.2 ± 1.6) × 10<sup>12</sup> cm<sup>–3</sup>, and they represent the average populations along the plasma column
in the capillary
Atmospheric Helium Capillary Dielectric Barrier Discharge for Soft Ionization: Determination of Atom Number Densities in the Lowest Excited and Metastable States
The populations of the lowest excited
helium states 2s <sup>3</sup>S<sub>1</sub>, 2s <sup>1</sup>S, 2p <sup>3</sup>P<sup>0</sup><sub>J</sub>, and 2p <sup>1</sup>P<sup>0</sup> created in an atmospheric
helium capillary dielectric barrier discharge were determined by means
of optical emission spectroscopy. The emitted intensities of 388,
501, 587, and 667 nm lines were measured side-on and end-on with respect
to the discharge axis. The comparison of optically thin side-on spectra
with end-on spectra, which exhibited the absorption effects in the
line kernels, enabled the determination of the average values of the
number densities <i>n</i><sub>1</sub> in the considered
He states along the plasma length <i>L</i>. The field of
the theoretical profiles for a series of the <i>n</i><sub>1</sub><i>L</i> parameters pertinent to the experimental
conditions was calculated for each line. By introducing the experimental
data into the field of calculated curves, <i>n</i><sub>1</sub><i>L</i> corresponding to the particular state could be
obtained. The measurements of the emission profiles were done as a
function of the discharge voltage in the range covering homogeneous
as well as filamentary DBD operation mode. Due to nonuniformity of
the excited atom density distribution along the plasma, the values
of <i>n</i><sub>1</sub> could be obtained only in the homogeneous
operation mode where the nonuniformity was small. The following maximum
values were found for the number densities in the investigated states: <i>n</i><sub>1</sub><sup>av</sup> (2s <sup>3</sup>S<sub>1</sub>) = (2.9 ± 1.1) × 10<sup>13</sup> cm<sup>–3</sup>, <i>n</i><sub>1</sub><sup>av</sup> (2s <sup>1</sup>S) = (1.4 ±
0.5) × 10<sup>13</sup> cm<sup>–3</sup>, <i>n</i><sub>1</sub><sup>av</sup> (2p <sup>3</sup>P<sup>0</sup><sub>J</sub>) = (1.1 ± 0.4) × 10<sup>13</sup> cm<sup>–3</sup>, <i>n</i><sub>1</sub><sup>av</sup> (2p <sup>1</sup>P<sup>0</sup>) = (4.2 ± 1.6) × 10<sup>12</sup> cm<sup>–3</sup>, and they represent the average populations along the plasma column
in the capillary
Atmospheric Helium Capillary Dielectric Barrier Discharge for Soft Ionization: Determination of Atom Number Densities in the Lowest Excited and Metastable States
The populations of the lowest excited
helium states 2s <sup>3</sup>S<sub>1</sub>, 2s <sup>1</sup>S, 2p <sup>3</sup>P<sup>0</sup><sub>J</sub>, and 2p <sup>1</sup>P<sup>0</sup> created in an atmospheric
helium capillary dielectric barrier discharge were determined by means
of optical emission spectroscopy. The emitted intensities of 388,
501, 587, and 667 nm lines were measured side-on and end-on with respect
to the discharge axis. The comparison of optically thin side-on spectra
with end-on spectra, which exhibited the absorption effects in the
line kernels, enabled the determination of the average values of the
number densities <i>n</i><sub>1</sub> in the considered
He states along the plasma length <i>L</i>. The field of
the theoretical profiles for a series of the <i>n</i><sub>1</sub><i>L</i> parameters pertinent to the experimental
conditions was calculated for each line. By introducing the experimental
data into the field of calculated curves, <i>n</i><sub>1</sub><i>L</i> corresponding to the particular state could be
obtained. The measurements of the emission profiles were done as a
function of the discharge voltage in the range covering homogeneous
as well as filamentary DBD operation mode. Due to nonuniformity of
the excited atom density distribution along the plasma, the values
of <i>n</i><sub>1</sub> could be obtained only in the homogeneous
operation mode where the nonuniformity was small. The following maximum
values were found for the number densities in the investigated states: <i>n</i><sub>1</sub><sup>av</sup> (2s <sup>3</sup>S<sub>1</sub>) = (2.9 ± 1.1) × 10<sup>13</sup> cm<sup>–3</sup>, <i>n</i><sub>1</sub><sup>av</sup> (2s <sup>1</sup>S) = (1.4 ±
0.5) × 10<sup>13</sup> cm<sup>–3</sup>, <i>n</i><sub>1</sub><sup>av</sup> (2p <sup>3</sup>P<sup>0</sup><sub>J</sub>) = (1.1 ± 0.4) × 10<sup>13</sup> cm<sup>–3</sup>, <i>n</i><sub>1</sub><sup>av</sup> (2p <sup>1</sup>P<sup>0</sup>) = (4.2 ± 1.6) × 10<sup>12</sup> cm<sup>–3</sup>, and they represent the average populations along the plasma column
in the capillary
Atmospheric Helium Capillary Dielectric Barrier Discharge for Soft Ionization: Determination of Atom Number Densities in the Lowest Excited and Metastable States
The populations of the lowest excited
helium states 2s <sup>3</sup>S<sub>1</sub>, 2s <sup>1</sup>S, 2p <sup>3</sup>P<sup>0</sup><sub>J</sub>, and 2p <sup>1</sup>P<sup>0</sup> created in an atmospheric
helium capillary dielectric barrier discharge were determined by means
of optical emission spectroscopy. The emitted intensities of 388,
501, 587, and 667 nm lines were measured side-on and end-on with respect
to the discharge axis. The comparison of optically thin side-on spectra
with end-on spectra, which exhibited the absorption effects in the
line kernels, enabled the determination of the average values of the
number densities <i>n</i><sub>1</sub> in the considered
He states along the plasma length <i>L</i>. The field of
the theoretical profiles for a series of the <i>n</i><sub>1</sub><i>L</i> parameters pertinent to the experimental
conditions was calculated for each line. By introducing the experimental
data into the field of calculated curves, <i>n</i><sub>1</sub><i>L</i> corresponding to the particular state could be
obtained. The measurements of the emission profiles were done as a
function of the discharge voltage in the range covering homogeneous
as well as filamentary DBD operation mode. Due to nonuniformity of
the excited atom density distribution along the plasma, the values
of <i>n</i><sub>1</sub> could be obtained only in the homogeneous
operation mode where the nonuniformity was small. The following maximum
values were found for the number densities in the investigated states: <i>n</i><sub>1</sub><sup>av</sup> (2s <sup>3</sup>S<sub>1</sub>) = (2.9 ± 1.1) × 10<sup>13</sup> cm<sup>–3</sup>, <i>n</i><sub>1</sub><sup>av</sup> (2s <sup>1</sup>S) = (1.4 ±
0.5) × 10<sup>13</sup> cm<sup>–3</sup>, <i>n</i><sub>1</sub><sup>av</sup> (2p <sup>3</sup>P<sup>0</sup><sub>J</sub>) = (1.1 ± 0.4) × 10<sup>13</sup> cm<sup>–3</sup>, <i>n</i><sub>1</sub><sup>av</sup> (2p <sup>1</sup>P<sup>0</sup>) = (4.2 ± 1.6) × 10<sup>12</sup> cm<sup>–3</sup>, and they represent the average populations along the plasma column
in the capillary
Atmospheric Helium Capillary Dielectric Barrier Discharge for Soft Ionization: Determination of Atom Number Densities in the Lowest Excited and Metastable States
The populations of the lowest excited
helium states 2s <sup>3</sup>S<sub>1</sub>, 2s <sup>1</sup>S, 2p <sup>3</sup>P<sup>0</sup><sub>J</sub>, and 2p <sup>1</sup>P<sup>0</sup> created in an atmospheric
helium capillary dielectric barrier discharge were determined by means
of optical emission spectroscopy. The emitted intensities of 388,
501, 587, and 667 nm lines were measured side-on and end-on with respect
to the discharge axis. The comparison of optically thin side-on spectra
with end-on spectra, which exhibited the absorption effects in the
line kernels, enabled the determination of the average values of the
number densities <i>n</i><sub>1</sub> in the considered
He states along the plasma length <i>L</i>. The field of
the theoretical profiles for a series of the <i>n</i><sub>1</sub><i>L</i> parameters pertinent to the experimental
conditions was calculated for each line. By introducing the experimental
data into the field of calculated curves, <i>n</i><sub>1</sub><i>L</i> corresponding to the particular state could be
obtained. The measurements of the emission profiles were done as a
function of the discharge voltage in the range covering homogeneous
as well as filamentary DBD operation mode. Due to nonuniformity of
the excited atom density distribution along the plasma, the values
of <i>n</i><sub>1</sub> could be obtained only in the homogeneous
operation mode where the nonuniformity was small. The following maximum
values were found for the number densities in the investigated states: <i>n</i><sub>1</sub><sup>av</sup> (2s <sup>3</sup>S<sub>1</sub>) = (2.9 ± 1.1) × 10<sup>13</sup> cm<sup>–3</sup>, <i>n</i><sub>1</sub><sup>av</sup> (2s <sup>1</sup>S) = (1.4 ±
0.5) × 10<sup>13</sup> cm<sup>–3</sup>, <i>n</i><sub>1</sub><sup>av</sup> (2p <sup>3</sup>P<sup>0</sup><sub>J</sub>) = (1.1 ± 0.4) × 10<sup>13</sup> cm<sup>–3</sup>, <i>n</i><sub>1</sub><sup>av</sup> (2p <sup>1</sup>P<sup>0</sup>) = (4.2 ± 1.6) × 10<sup>12</sup> cm<sup>–3</sup>, and they represent the average populations along the plasma column
in the capillary
Atmospheric Helium Capillary Dielectric Barrier Discharge for Soft Ionization: Determination of Atom Number Densities in the Lowest Excited and Metastable States
The populations of the lowest excited
helium states 2s <sup>3</sup>S<sub>1</sub>, 2s <sup>1</sup>S, 2p <sup>3</sup>P<sup>0</sup><sub>J</sub>, and 2p <sup>1</sup>P<sup>0</sup> created in an atmospheric
helium capillary dielectric barrier discharge were determined by means
of optical emission spectroscopy. The emitted intensities of 388,
501, 587, and 667 nm lines were measured side-on and end-on with respect
to the discharge axis. The comparison of optically thin side-on spectra
with end-on spectra, which exhibited the absorption effects in the
line kernels, enabled the determination of the average values of the
number densities <i>n</i><sub>1</sub> in the considered
He states along the plasma length <i>L</i>. The field of
the theoretical profiles for a series of the <i>n</i><sub>1</sub><i>L</i> parameters pertinent to the experimental
conditions was calculated for each line. By introducing the experimental
data into the field of calculated curves, <i>n</i><sub>1</sub><i>L</i> corresponding to the particular state could be
obtained. The measurements of the emission profiles were done as a
function of the discharge voltage in the range covering homogeneous
as well as filamentary DBD operation mode. Due to nonuniformity of
the excited atom density distribution along the plasma, the values
of <i>n</i><sub>1</sub> could be obtained only in the homogeneous
operation mode where the nonuniformity was small. The following maximum
values were found for the number densities in the investigated states: <i>n</i><sub>1</sub><sup>av</sup> (2s <sup>3</sup>S<sub>1</sub>) = (2.9 ± 1.1) × 10<sup>13</sup> cm<sup>–3</sup>, <i>n</i><sub>1</sub><sup>av</sup> (2s <sup>1</sup>S) = (1.4 ±
0.5) × 10<sup>13</sup> cm<sup>–3</sup>, <i>n</i><sub>1</sub><sup>av</sup> (2p <sup>3</sup>P<sup>0</sup><sub>J</sub>) = (1.1 ± 0.4) × 10<sup>13</sup> cm<sup>–3</sup>, <i>n</i><sub>1</sub><sup>av</sup> (2p <sup>1</sup>P<sup>0</sup>) = (4.2 ± 1.6) × 10<sup>12</sup> cm<sup>–3</sup>, and they represent the average populations along the plasma column
in the capillary
Systematic Comparison between Half and Full Dielectric Barrier Discharges Based on the Low Temperature Plasma Probe (LTP) and Dielectric Barrier Discharge for Soft Ionization (DBDI) Configurations
Dielectric
barrier discharge (DBD)-based analytical applications
have experienced rapid development in recent years. DBD designs and
parameters and the application they are used for can vary considerably.
This leads to a diverse field with many apparently unique systems
that are all based on the same physical principle. The most significant
changes among DBDs used for chemical analysis are in how the discharge
electrodes are separated from the ignited discharge gas. While the
official definition of a DBD states that at least one electrode has
to be covered by a dielectric to be considered a DBD, configurations
with both electrodes covered by dielectric layers can also be realized.
The electrode surface plays a major role in several plasma-related
technical fields, surface treatment or sputtering processes, for example,
and has hence been studied in great detail. Analytical DBDs are often
operated at low power and atmospheric pressure, making a direct transfer
of insight and know-how gained from the aforementioned well-studied
fields complicated. This work focuses on comparing two DBD configurations:
the low temperature plasma probe (LTP) and the dielectric barrier
discharge for soft ionization (DBDI). The LTP is representative of
a DBD with one covered electrode and the DBDI of a design in which
both electrodes are covered. These two configurations are well suited
for a systematic comparison due to their similar geometric designs
based on a dielectric capillary