Physical Review Letters

Resolution of |ml| and |mj| Levels in the Electric Field Ionization of Highly Excited d States of Na

Thomas F. Gallagher, L. M. Humphrey, R. M. Hill, S. A. Edelstein

Published Nov 29, 1976• 73 citations

Abstract

In the electric field ionization of highly excited $s$, $p$, and $d$ states of Na, we have observed one, two, and three ionization thresholds, respectively, reflecting the number of high-field $|{m}_{l}|$ states coming from the $s$, $p$, and $d$ states. Our observations indicate that the passage from low to intermediate field is adiabatic, and as a consequence we are able to achieve selective ionization of essentially degenerate low-field $|{m}_{l}|$ fine-structure levels.

DOI: 10.1103/physrevlett.37.1465

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Physical Review Letters

Resolution of |ml| and |mj| Levels in the Electric Field Ionization of Highly Excited d States of Na

Thomas F. Gallagher, L. M. Humphrey, R. M. Hill, S. A. Edelstein

Published Nov 29, 1976• 73 citations

Publisher

Abstract

In the electric field ionization of highly excited

s

p

, and

d

states of Na, we have observed one, two, and three ionization thresholds, respectively, reflecting the number of high-field

|{m}_{l}|

states coming from the

s

p

, and

d

states. Our observations indicate that the passage from low to intermediate field is adiabatic, and as a consequence we are able to achieve selective ionization of essentially degenerate low-field

|{m}_{l}|

fine-structure levels.

DOI: 10.1103/physrevlett.37.1465

Related papers

Field ionization of highly excited states of sodium

Thomas F. Gallagher, L. M. Humphrey, William E. Cooke +2 more

We have observed the selective ionization of the degenerate $|{m}_{j}|$ levels of $s$ , $p$ , and $d$ states of sodium in the range of $n$ from 15 to 20 and have shown that atoms produced in these low-field (\ensuremath{\sim} 10 V/cm) states pass adiabatically from low-field $|{m}_{j}|$ to intermediate-field $|{m}_{l}|$ states. Experiments on the Stark manifold states in intermediate fields (\ensuremath{\sim} 1 kV/cm) and high fields (\ensuremath{\sim} 4 kV/cm) show that the $|{m}_{l}|=0 \mathrm{and} 1$ states pass adiabatically from intermediate- to high-field states and that the passage of the $|{m}_{l}|=2$ states is very nearly adiabatic. These findings suggest a general approach for predicting the threshold fields for ionization of atomic Rydberg states.We have observed the selective ionization of the degenerate $|{m}_{j}|$ levels of $s$, $p$, and $d$ states of sodium in the range of $n$ from 15 to 20 and have shown that atoms produced in these low-field (\ensuremath{\sim} 10 V/cm) states pass adiabatically from low-field $|{m}_{j}|$ to intermediate-field $|{m}_{l}|$ states. Experiments on the Stark manifold states in intermediate fields (\ensuremath{\sim} 1 kV/cm) and high fields (\ensuremath{\sim} 4 kV/cm) show that the $|{m}_{l}|=0 \mathrm{and} 1$ states pass adiabatically from intermediate- to high-field states and that the passage of the $|{m}_{l}|=2$ states is very nearly adiabatic. These findings suggest a general approach for predicting the threshold fields for ionization of atomic Rydberg states.

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We report the electric field ionization of the n=8--15 levels of Na using field pulses of rise time \ensuremath{\sim}1 \ensuremath{\mu}s. The passage from low to high field is adiabatic, and the fields required for \ensuremath{\Vert} ${m}_{l}$ \ensuremath{\Vert}=0, 1, and 2 states are 3.12(9)\ifmmode\times\else\texttimes\fi{} ${10}^{8}$ ${n}_{s}^{\mathrm{\ensuremath{-}}4}$ V/cm, 3.37(11)\ifmmode\times\else\texttimes\fi{} ${10}^{8}$ ${n}_{s}^{\mathrm{\ensuremath{-}}4}$ V/cm, and 3.68(21)\ifmmode\times\else\texttimes\fi{} ${10}^{8}$ ${n}_{s}^{\mathrm{\ensuremath{-}}4}$ V/cm. Here ${n}_{s}$ is the effective quantum number in the ionizing field. These values are in agreement with those determined previously for higher-lying states.We report the electric field ionization of the n=8--15 levels of Na using field pulses of rise time \ensuremath{\sim}1 \ensuremath{\mu}s. The passage from low to high field is adiabatic, and the fields required for \ensuremath{\Vert}${m}_{l}$\ensuremath{\Vert}=0, 1, and 2 states are 3.12(9)\ifmmode\times\else\texttimes\fi{}${10}^{8}$${n}_{s}^{\mathrm{\ensuremath{-}}4}$ V/cm, 3.37(11)\ifmmode\times\else\texttimes\fi{}${10}^{8}$${n}_{s}^{\mathrm{\ensuremath{-}}4}$ V/cm, and 3.68(21)\ifmmode\times\else\texttimes\fi{}${10}^{8}$${n}_{s}^{\mathrm{\ensuremath{-}}4}$ V/cm. Here ${n}_{s}$ is the effective quantum number in the ionizing field. These values are in agreement with those determined previously for higher-lying states.

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Ionization of Na atoms by 8-GHz electric fields

H. B. van Linden van den Heuvell, Thomas F. Gallagher

The ionization of Na atoms by 8-GHz electric fields from principal quantum number n=16--42 exhibits a threshold for the \ensuremath{\Vert}m\ensuremath{\Vert}=0 and 1 states of E\ensuremath{\approxeq}1/3 ${n}^{5}$ , and two thresholds for the \ensuremath{\Vert}m\ensuremath{\Vert}=2 states of E\ensuremath{\approxeq}1/9 ${n}^{4}$ and E\ensuremath{\approxeq}1/21 ${n}^{4}$ depending upon the n state. The \ensuremath{\Vert}m\ensuremath{\Vert}=0 and 1 thresholds show a departure from a 1/ ${n}^{5}$ scaling at high n which we interpret as being due to the fact that the relatively slower atomic frequencies at high n no longer match the 8 GHz microwave frequency. The E=1/21 ${n}^{4}$ \ensuremath{\Vert}m\ensuremath{\Vert}=2 threshold has not to our knowledge been observed before, and we interpret it as arising from the ionization of the highest energy, or blue, Stark state at the classical limit for ionization.The ionization of Na atoms by 8-GHz electric fields from principal quantum number n=16--42 exhibits a threshold for the \ensuremath{\Vert}m\ensuremath{\Vert}=0 and 1 states of E\ensuremath{\approxeq}1/3${n}^{5}$, and two thresholds for the \ensuremath{\Vert}m\ensuremath{\Vert}=2 states of E\ensuremath{\approxeq}1/9${n}^{4}$ and E\ensuremath{\approxeq}1/21${n}^{4}$ depending upon the n state. The \ensuremath{\Vert}m\ensuremath{\Vert}=0 and 1 thresholds show a departure from a 1/${n}^{5}$ scaling at high n which we interpret as being due to the fact that the relatively slower atomic frequencies at high n no longer match the 8 GHz microwave frequency. The E=1/21${n}^{4}$ \ensuremath{\Vert}m\ensuremath{\Vert}=2 threshold has not to our knowledge been observed before, and we interpret it as arising from the ionization of the highest energy, or blue, Stark state at the classical limit for ionization.

Physical Review ASep 1, 198520 citations

In the electric field ionization of highly excited

s

p

, and

d

states of Na, we have observed one, two, and three ionization thresholds, respectively, reflecting the number of high-field

|{m}_{l}|

states coming from the

s

p

, and

d

states. Our observations indicate that the passage from low to intermediate field is adiabatic, and as a consequence we are able to achieve selective ionization of essentially degenerate low-field

|{m}_{l}|

fine-structure levels.

We have observed the selective ionization of the degenerate

|{m}_{j}|

levels of

s

p

, and

d

states of sodium in the range of

n

from 15 to 20 and have shown that atoms produced in these low-field (\ensuremath{\sim} 10 V/cm) states pass adiabatically from low-field

|{m}_{j}|

to intermediate-field

|{m}_{l}|

states. Experiments on the Stark manifold states in intermediate fields (\ensuremath{\sim} 1 kV/cm) and high fields (\ensuremath{\sim} 4 kV/cm) show that the

|{m}_{l}|=0 \mathrm{and} 1

states pass adiabatically from intermediate- to high-field states and that the passage of the

|{m}_{l}|=2

states is very nearly adiabatic. These findings suggest a general approach for predicting the threshold fields for ionization of atomic Rydberg states.

{m}_{l}

\ensuremath{\Vert}=0, 1, and 2 states are 3.12(9)\ifmmode\times\else\texttimes\fi{}

{10}^{8}

${n}_{s}^{\mathrm{\ensuremath{-}}4}$ V/cm, 3.37(11)\ifmmode\times\else\texttimes\fi{}

{10}^{8}

${n}_{s}^{\mathrm{\ensuremath{-}}4}$ V/cm, and 3.68(21)\ifmmode\times\else\texttimes\fi{}

{10}^{8}

${n}_{s}^{\mathrm{\ensuremath{-}}4}$ V/cm. Here

{n}_{s}

is the effective quantum number in the ionizing field. These values are in agreement with those determined previously for higher-lying states.

{n}^{5}

, and two thresholds for the \ensuremath{\Vert}m\ensuremath{\Vert}=2 states of E\ensuremath{\approxeq}1/9

{n}^{4}

and E\ensuremath{\approxeq}1/21

{n}^{4}

depending upon the n state. The \ensuremath{\Vert}m\ensuremath{\Vert}=0 and 1 thresholds show a departure from a 1/

{n}^{5}

scaling at high n which we interpret as being due to the fact that the relatively slower atomic frequencies at high n no longer match the 8 GHz microwave frequency. The E=1/21

{n}^{4}

\ensuremath{\Vert}m\ensuremath{\Vert}=2 threshold has not to our knowledge been observed before, and we interpret it as arising from the ionization of the highest energy, or blue, Stark state at the classical limit for ionization.