Fission of $$^{180}$$Hg and $$^{264}$$Fm: a comparative study

Abstract $$^{180}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mmultiscripts> <mml:mrow/> <mml:mrow/> <mml:mn>180</mml:mn> </mml:mmultiscripts> </mml:math> Hg is experimentally found to fission asymmetrically. This result was not expected as a naive fragment shell effects study would support the symmetric mode to be the most probable. In the present study we investigate both symmetric and asymmetric $$^{180}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mmultiscripts> <mml:mrow/> <mml:mrow/> <mml:mn>180</mml:mn> </mml:mmultiscripts> </mml:math> Hg fission modes at the mean field level using various multipole moment constraints. Potential energy surfaces are analysed in terms of shell effects that shape their topographies and connections to fragment shell effects are made. The non-occurrence of low energy symmetric fission is interpreted in terms of $$^{90}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mmultiscripts> <mml:mrow/> <mml:mrow/> <mml:mn>90</mml:mn> </mml:mmultiscripts> </mml:math> Zr fragment properties. Throughout this study a comparison with $$^{264}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mmultiscripts> <mml:mrow/> <mml:mrow/> <mml:mn>264</mml:mn> </mml:mmultiscripts> </mml:math> Fm and its symmetric doubly magic $$^{132}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mmultiscripts> <mml:mrow/> <mml:mrow/> <mml:mn>132</mml:mn> </mml:mmultiscripts> </mml:math> Sn fission fragments is done.