Isotope shift refers to minute differences in the electronic energy levels of different isotopes of the same element that cause spectral lines to split or shift. There are two main types of isotope shift: mass shift, which is due to differences in nuclear mass, and field shift, which provides information on nuclear structure. One experiment measured the large isotope shift between hydrogen and deuterium spectra. Another studied differences in sonoluminescence spectra between helium-3 and helium-4 bubbles in water and heavy water. Isotope shift analysis relies on nuclear structure knowledge and determines electronic wavefunctions and shift parameters through fitting to experimental data.

1. ISOTOPE SHIFT
EXPERIMENT
Nuclear Physics-1
SYEDA NIMRA SALAMAT

2. Isotope shift:
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‘’ A displacement or splitting of spectral lines
indicating the presence of isotopes of an
element.”
Isotope shifts in atomic spectra are minute differences between the
electronic energy levels of different isotopes of the same element. If
atomic spectra also have hyperfine structure the shift refers to the
centre of gravity of the spectra.

3. Types of Isotope Shift:
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Mass Shift
(MS)
• In the lighter nuclei the MS is the
dominant shift that takes place, this
is due to the finite mass of the nuclei.
• The MS is due to the change in
kinetic energy of the nucleus, which
in turn depends on the nuclear mass.
Field Shift
(FS)
• In the heavier nuclei, the FS is
dominant, this is because of the none
zero nuclear volume. It is the field
shift, which provides information on
the radial parameters of the nucleus
and is therefore the part of interest in
nuclear physics.
• The FS is due to the change in the
spatial distribution of the nuclear
charge between isotopes.

4. Mass Shift (MS);
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1. Normal Mass Shift
(NMS)
• The NMS is due to the
difference in the reduced mass of
the electron-nucleus system and
is readily calculated.
2. Specific Mass Shift
(SMS)
• The SMS is due to momentum
correlations among electrons and
is not readily calculated.

5. Explanation:
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The technology of isotope shift covers many fields in chemistry, physics
, biology and even semiconductor technology. The main instrument used
in finding isotope shifts is the Spectroscope, this is an instrument that
breaks up a beam of light or other electromagnetic wave into the various
colours or wavelengths which are present, allows measurement of the
wavelengths of the various components. For visible light, the light is
normally broken up or dispersed with either a strong prism or a
diffraction grating.

6. ISOTOPE SHIFT Experiment:
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There are many experiments that have been done using isotope
shift technology. One of the main ones would be to see the
1. Isotope shift in the spectra of hydrogen and deuterium
2. Isotope effects in sonoluminescene
It is now known that most elements in nature consists of two or
more isotopes with the exception of beryllium, aluminium, phosphorus
and sodium. The latest research being done using isotope shift is as
various as the subject itself.

7. 1. Isotope shift in the spectra of hydrogen and deuterium;
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The mass effect explains the isotope shift of Hydrogen/Deuterium quite well.
Because this shift is quite large, approximately 1 Å, it can be observed also in the
case of Doppler-broadened lines. An estimate of the isotope shift can be obtained
from: (RH und RD are the Rydberg constants for Hydrogen and Deuterium,
respectively)
𝑅 𝐷
𝑅 𝐻
=
1+
𝑚 𝑒
𝑚 𝐻
1+
𝑚 𝑒
𝑚 𝐷
≈ (1+
𝑚 𝑒
𝑚 𝐻
)(1−
𝑚 𝑒
𝑚 𝐷
)
or with 𝑚 𝐷 ≈ 2𝑚 𝐻 𝑎𝑛𝑑
𝑚 𝑒
𝑚 𝐻
≈
1
1836
:
𝑅 𝐷
𝑅 𝐻
≈ 1 +
𝑚 𝑒
2𝑚 𝐻
= 1 +
1
2.1836

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and
𝑣 𝐷 = 𝑅 𝐷(
1
𝑛2 −
1
𝑛2) = 𝑅 𝐻 1 +
𝑚 𝑒
2𝑚 𝐻
1
𝑛2 −
1
𝑛2 = 𝑣 𝐻(1 +
1
2.1836
)
or
𝜆 𝐷 = 𝜆 𝐻 1 −
1
2.1836
and
∆𝜆 = 𝜆 𝐻 − 𝜆 𝐷 = 𝜆 𝐻 (
1
2.1836
)
It is clear that the Deuterium lines are shifted to shorter wavelengths. The magnitude
of the shift is proportional to the wavelength.

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10. 2. Isotope effects in sonoluminescene;
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The only pure liquids in which sonoluminescence (is a
phenomenon that occurs when a small gas bubble is periodically driven
in a liquid solution at ultrasonic frequencies, resulting in bubble
collapse, and light emission) from a single stable bubble has been
observed are water and heavy water. With regard to the content of the
trapped bubble there are a number of gases which yield light. Helium is
particularly interesting because its spectrum is strongly peaked in the far
ultraviolet. In order to learn about the mechanism responsible for
sonoluminescence, the search is on for differences between the spectra
of He[sup 4] and He[sup 3] bubbles in water and heavy water.

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12. Single-Bubble Multi-Bubble
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13. CONCLUSION:
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The understanding of atomic isotope shifts relies partly on the knowledge
of nuclear structure and provide information of the structure of nuclei. The
analyses of isotope shifts are similar to those of hyperfine structures in that
they consist of two steps.
 First, through the parametric study of the level energies, the angular
wavefunctions of the levels in intermediate coupling are determined.
 Second, through least-squares fitting procedure, the values of the isotope
shift parameters are adjusted so that experimental shift values can be
reproduced in the most accurate way.
The isotope shift is the sum of two terms: the mass effect and the field effect.
If only one isotope pair is available, the experiment only yields this sum but
not the respective contributions of the two effects.

14. HOPE FOR THE BEST
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THANK YOU 