Charge radii and electromagnetic moments of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mmultiscripts> <mml:mi>Bi</mml:mi> <mml:mprescripts/> <mml:none/> <mml:mrow> <mml:mn>214</mml:mn> <mml:mo>−</mml:mo> <mml:mn>218</mml:mn> </mml:mrow> </mml:mmultiscripts> </mml:math> : Exploring the “southern” border of the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>Z</mml:mi> <mml:mo>></mml:mo> <mml:mn>82</mml:mn> </mml:mrow> </mml:math> octupole-deformation region
Abstract
The changes in the mean-squared charge radii relative to <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"> <a:mmultiscripts> <a:mi>Bi</a:mi> <a:mn>126</a:mn> <a:none/> <a:mprescripts/> <a:none/> <a:mn>209</a:mn> </a:mmultiscripts> </a:math> ( <b:math xmlns:b="http://www.w3.org/1998/Math/MathML"> <b:mrow> <b:mi>δ</b:mi> <b:msup> <b:mrow> <b:mo>〈</b:mo> <b:msup> <b:mi>r</b:mi> <b:mn>2</b:mn> </b:msup> <b:mo>〉</b:mo> </b:mrow> <b:mrow> <b:mi>N</b:mi> <b:mo>,</b:mo> <b:mn>126</b:mn> </b:mrow> </b:msup> </b:mrow> </b:math> ) and the magnetic dipole and electric quadrupole moments in <c:math xmlns:c="http://www.w3.org/1998/Math/MathML"> <c:mmultiscripts> <c:mi>Bi</c:mi> <c:mprescripts/> <c:none/> <c:mrow> <c:mn>214</c:mn> <c:mo>−</c:mo> <c:mn>218</c:mn> </c:mrow> </c:mmultiscripts> </c:math> have been measured using the in-source resonance-ionization spectroscopy technique at ISOLDE (CERN). Magnetic moments of odd-odd bismuth nuclei have been analyzed by the additivity relation. Previous tentative spin-parity and configuration assignments based on the <d:math xmlns:d="http://www.w3.org/1998/Math/MathML"> <d:mi>β</d:mi> </d:math> -decay feeding patterns have been supported. A normal odd-even staggering in charge radii of bismuth isotopes with <e:math xmlns:e="http://www.w3.org/1998/Math/MathML"> <e:mrow> <e:mi>N</e:mi> <e:mo>></e:mo> <e:mn>126</e:mn> </e:mrow> </e:math> has been observed. The new data for the <f:math xmlns:f="http://www.w3.org/1998/Math/MathML"> <f:mrow> <f:mi>δ</f:mi> <f:mo>〈</f:mo> <f:msup> <f:mi>r</f:mi> <f:mn>2</f:mn> </f:msup> <f:mo>〉</f:mo> </f:mrow> </f:math> of bismuth isotopes allow a study of the isotonic dependencies in the charge radii, revealing jumps in <g:math xmlns:g="http://www.w3.org/1998/Math/MathML"> <g:mrow> <g:mi>δ</g:mi> <g:msup> <g:mrow> <g:mo>〈</g:mo> <g:msup> <g:mi>r</g:mi> <g:mn>2</g:mn> </g:msup> <g:mo>〉</g:mo> </g:mrow> <g:mrow> <g:mn>132</g:mn> <g:mo>,</g:mo> <g:mn>126</g:mn> </g:mrow> </g:msup> </g:mrow> </g:math> and <h:math xmlns:h="http://www.w3.org/1998/Math/MathML"> <h:mrow> <h:mi>δ</h:mi> <h:msup> <h:mrow> <h:mo>〈</h:mo> <h:msup> <h:mi>r</h:mi> <h:mn>2</h:mn> </h:msup> <h:mo>〉</h:mo> </h:mrow> <h:mrow> <h:mn>134</h:mn> <h:mo>,</h:mo> <h:mn>126</h:mn> </h:mrow> </h:msup> </h:mrow> </h:math> at <i:math xmlns:i="http://www.w3.org/1998/Math/MathML"> <i:mrow> <i:mi>Z</i:mi> <i:mo>=</i:mo> <i:mn>84</i:mn> </i:mrow> </i:math> . This pattern could be explained by a sudden onset of octupole deformation at <j:math xmlns:j="http://www.w3.org/1998/Math/MathML"> <j:mrow> <j:mi>N</j:mi> <j:mo>=</j:mo> <j:mn>132</j:mn> </j:mrow> </j:math> and 134 when going from polonium ( <k:math xmlns:k="http://www.w3.org/1998/Math/MathML"> <k:mrow> <k:mi>Z</k:mi> <k:mo>=</k:mo> <k:mn>84</k:mn> </k:mrow> </k:math> ) to astatine ( <l:math xmlns:l="http://www.w3.org/1998/Math/MathML"> <l:mrow> <l:mi>Z</l:mi> <l:mo>=</l:mo> <l:mn>85</l:mn> </l:mrow> </l:math> ).