Experimental Techniques for Determining Spin States

The ratio of the ${g}_{J}$ factor of $^{4}\mathrm{He}(2^{3}S_{1})$ to that of $^{87}\mathrm{Rb}(5^{2}S_{\frac{1}{2}})$ has been measured to a fractional accuracy of \ifmmode\pm\else\textpm\fi{}5\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}8}$. The Rb atoms were optically pumped, and the $^{4}\mathrm{He}(2^{3}S_{1})$ Zeeman resonance was observed through a combination of spin-exchange collisions and spin-dependent Penning ionization. Linewidths as narrow as 220 Hz were observed for the $^{4}\mathrm{He}(2^{3}S_{1})$ Zeeman resonance. The accuracy of this experiment was limited by a systematic shift in the He ${g}_{J}$ factor that depended upon the intensity of the discharge used to excite the He atoms to the $2^{3}S_{1}$ state. Calculations indicate that transfer of coherence in spin-exchange collisions with free electrons contributes to this shift. The measured ratio $\frac{{g}_{J}(^{4}\mathrm{He}, 2^{3}S_{1})}{{g}_{J}(^{87}\mathrm{Rb}, 5^{2}S_{\frac{1}{2}})}=1\ensuremath{-}46.798(50)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$. Using the previously measured ratio of the ${g}_{J}$ factors of the ground state of rubidium to the ground state of hydrogen, we determine the ratio $\frac{{g}_{J}(^{4}\mathrm{He}, 2^{3}S_{1})}{{g}_{J}(^{1}\mathrm{H}, 1^{2}S_{\frac{1}{2}})}=1\ensuremath{-}23.214(50)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$. This result agrees with recent theoretical calculations and experimental determinations using atomic-beam techniques, but disagrees with an earlier experimental determination using optical-pumping techniques.The ratio of the ${g}_{J}$ factor of $^{4}\mathrm{He}(2^{3}S_{1})$ to that of $^{87}\mathrm{Rb}(5^{2}S_{\frac{1}{2}})$ has been measured to a fractional accuracy of \ifmmode\pm\else\textpm\fi{}5\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}8}$. The Rb atoms were optically pumped, and the $^{4}\mathrm{He}(2^{3}S_{1})$ Zeeman resonance was observed through a combination of spin-exchange collisions and spin-dependent Penning ionization. Linewidths as narrow as 220 Hz were observed for the $^{4}\mathrm{He}(2^{3}S_{1})$ Zeeman resonance. The accuracy of this experiment was limited by a systematic shift in the He ${g}_{J}$ factor that depended upon the intensity of the discharge used to excite the He atoms to the $2^{3}S_{1}$ state. Calculations indicate that transfer of coherence in spin-exchange collisions with free electrons contributes to this shift. The measured ratio $\frac{{g}_{J}(^{4}\mathrm{He}, 2^{3}S_{1})}{{g}_{J}(^{87}\mathrm{Rb}, 5^{2}S_{\frac{1}{2}})}=1\ensuremath{-}46.798(50)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$. Using the previously measured ratio of the ${g}_{J}$ factors of the ground state of rubidium to the ground state of hydrogen, we determine the ratio $\frac{{g}_{J}(^{4}\mathrm{He}, 2^{3}S_{1})}{{g}_{J}(^{1}\mathrm{H}, 1^{2}S_{\frac{1}{2}})}=1\ensuremath{-}23.214(50)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$. This result agrees with recent theoretical calculations and experimental determinations using atomic-beam techniques, but disagrees with an earlier experimental determination using optical-pumping techniques.

Physical Review ASep 1, 197722 citations

Spin Measurements

Cosimo Bambi

Springer eBooksJan 1, 20220 citations

Manipulation and measurement of quantum states of single spins

Wrachtrup

Conference on Lasers and Electro-OpticsJan 1, 20040 citations

Ground State Polarized Photofragments Study by Using Resonance and Off-Resonance Probe Beam Techniques

B. V. Picheyev, Andrey G. Smolin, Oleg S. Vasyutinskii

The optical magnetic birefringence (Faraday) technique that can be used to study the anisotropy distributions of the angular momenta of photofragments produced in molecular photodissociation is compared theoretically and experimentally with the magnetic dichroism technique. The frame independent tensor form of the general expression describing the difference between an initial and a final polarization matrix of a probe light beam passing through the photofragment vapor is presented and analyzed. The procedure of detection of the photofragment electron orientation and alignment angular distributions by Doppler spectroscopy using each of the techniques is studied theoretically. The angular independent anisotropy orientation and alignment parameters describing photodissociation dynamics that can be determined from these studies are presented. It is shown that in principle each of the techniques can give the same information about the photodissociation dynamics; however, the birefringence technique has an undeniable advantage since it leads to an increase in accuracy of the experimental data. Both magnetic birefringence and magnetic dichroism techniques were used experimentally to study the spin orientation of ground state Rb atoms produced in photodissociation of RbI at 266 nm by circularly polarized laser light. The experiment was not of the Doppler spectroscopy type, but use of different 85 Rb and 87 Rb isotopes in the dissociation cell and in the probe light source allows detection of the oriented atomic photofragments separately by each of the techniques. Obtained experimental results are in agreement with the theoretical predictions. Contribution of the orientation of the Rb hyperfine structure energy states to the observed signals were also studied and treated theoretically. The initial degree of the electron spin orientation of the Rb atoms produced in the reaction was found to be P e = 0.11 ± 0.02.The optical magnetic birefringence (Faraday) technique that can be used to study the anisotropy distributions of the angular momenta of photofragments produced in molecular photodissociation is compared theoretically and experimentally with the magnetic dichroism technique. The frame independent tensor form of the general expression describing the difference between an initial and a final polarization matrix of a probe light beam passing through the photofragment vapor is presented and analyzed. The procedure of detection of the photofragment electron orientation and alignment angular distributions by Doppler spectroscopy using each of the techniques is studied theoretically. The angular independent anisotropy orientation and alignment parameters describing photodissociation dynamics that can be determined from these studies are presented. It is shown that in principle each of the techniques can give the same information about the photodissociation dynamics; however, the birefringence technique has an undeniable advantage since it leads to an increase in accuracy of the experimental data. Both magnetic birefringence and magnetic dichroism techniques were used experimentally to study the spin orientation of ground state Rb atoms produced in photodissociation of RbI at 266 nm by circularly polarized laser light. The experiment was not of the Doppler spectroscopy type, but use of different 85 Rb and 87 Rb isotopes in the dissociation cell and in the probe light source allows detection of the oriented atomic photofragments separately by each of the techniques. Obtained experimental results are in agreement with the theoretical predictions. Contribution of the orientation of the Rb hyperfine structure energy states to the observed signals were also studied and treated theoretically. The initial degree of the electron spin orientation of the Rb atoms produced in the reaction was found to be P e = 0.11 ± 0.02.

The Journal of Physical Chemistry AOct 1, 199766 citations

Sodium excitation by spin-polarized electrons: A reanalysis of existing experiments

N. Andersen, Klaus Bartschat

We generalize the existing description of collision-induced atomic S\ensuremath{\leftrightarrows}P transitions by spin-polarized electrons on spin-polarized target atoms. Analysis of existing experimental and theoretical data on the 3s\ensuremath{\leftrightarrows}3p transitions in Na determines how closely the ``perfect scattering experiment'' has been achieved to date. Using a newly developed inversion technique, we demonstrate to what extent the various scattering amplitudes can be extracted from present experiments, and how state-of-the-art theory can be used to remove the remaining ambiguities.We generalize the existing description of collision-induced atomic S\ensuremath{\leftrightarrows}P transitions by spin-polarized electrons on spin-polarized target atoms. Analysis of existing experimental and theoretical data on the 3s\ensuremath{\leftrightarrows}3p transitions in Na determines how closely the ``perfect scattering experiment'' has been achieved to date. Using a newly developed inversion technique, we demonstrate to what extent the various scattering amplitudes can be extracted from present experiments, and how state-of-the-art theory can be used to remove the remaining ambiguities.

Physical Review AMay 1, 19942 citations

Spin States and Spin Polarization

Hans Paetz gen. Schieck

Lecture notes in physicsNov 1, 20110 citations

The ratio of the

{g}_{J}

factor of

^{4}\mathrm{He}(2^{3}S_{1})

to that of

^{87}\mathrm{Rb}(5^{2}S_{\frac{1}{2}})

has been measured to a fractional accuracy of \ifmmode\pm\else\textpm\fi{}5\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}8}$. The Rb atoms were optically pumped, and the

^{4}\mathrm{He}(2^{3}S_{1})

Zeeman resonance was observed through a combination of spin-exchange collisions and spin-dependent Penning ionization. Linewidths as narrow as 220 Hz were observed for the

^{4}\mathrm{He}(2^{3}S_{1})

Zeeman resonance. The accuracy of this experiment was limited by a systematic shift in the He

{g}_{J}

factor that depended upon the intensity of the discharge used to excite the He atoms to the

2^{3}S_{1}

state. Calculations indicate that transfer of coherence in spin-exchange collisions with free electrons contributes to this shift. The measured ratio $\frac{{g}_{J}(^{4}\mathrm{He}, 2^{3}S_{1})}{{g}_{J}(^{87}\mathrm{Rb}, 5^{2}S_{\frac{1}{2}})}=1\ensuremath{-}46.798(50)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$. Using the previously measured ratio of the

{g}_{J}

factors of the ground state of rubidium to the ground state of hydrogen, we determine the ratio $\frac{{g}_{J}(^{4}\mathrm{He}, 2^{3}S_{1})}{{g}_{J}(^{1}\mathrm{H}, 1^{2}S_{\frac{1}{2}})}=1\ensuremath{-}23.214(50)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$. This result agrees with recent theoretical calculations and experimental determinations using atomic-beam techniques, but disagrees with an earlier experimental determination using optical-pumping techniques.