Direct measurement of the masses of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mmultiscripts><mml:mrow><mml:mi mathvariant="normal">Li</mml:mi></mml:mrow><mml:mprescripts/><mml:mrow/><mml:mrow><mml:mn>11</mml:mn></mml:mrow><mml:mrow/><mml:mrow/></mml:mmultiscripts></mml:mrow></mml:math>and<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mmultiscripts><mml:mrow><mml:mi mathvariant="normal">Na</mml:mi></mml:mrow><mml:mprescripts/><mml:mrow/><mml:mrow><mml:mn>2</mml:mn><mml:mn>6</mml:mn><mml:mo>−</mml:mo><mml:mn>3</mml:mn><mml:mn>2</mml:mn></mml:mrow><mml:mrow/><mml:mrow/></mml:mmultiscripts></mml:mrow></mml:math>with an on-line mass spectrometer

The use of an on-line mass spectrometer to make direct mass measurements of short-lived isotopes far from the stability line has been improved to yield more accurate mass measurements for $^{27\ensuremath{-}30}\mathrm{Na}$, new mass measurements for $^{11}\mathrm{Li}$, $^{31,32}\mathrm{Na}$, and to remove a discrepancy between existing mass measurements of $^{26}\mathrm{Na}$. The mass excesses (keV) measured are: $^{11}\mathrm{Li}$, 40940\ifmmode\pm\else\textpm\fi{}80; $^{26}\mathrm{Na}$, -6901\ifmmode\pm\else\textpm\fi{}25; $^{27}\mathrm{Na}$, -5620\ifmmode\pm\else\textpm\fi{}60; $^{28}\mathrm{Na}$, -1140\ifmmode\pm\else\textpm\fi{}80; $^{29}\mathrm{Na}$, 2650\ifmmode\pm\else\textpm\fi{}100; $^{30}\mathrm{Na}$, 8370\ifmmode\pm\else\textpm\fi{}200; $^{31}\mathrm{Na}$, 10600\ifmmode\pm\else\textpm\fi{}800; $^{32}\mathrm{Na}$, 16400\ifmmode\pm\else\textpm\fi{}1100. The $^{11}\mathrm{Li}$ value indicates that it is bound by only 170\ifmmode\pm\else\textpm\fi{}80 keV. The masses of $^{31}\mathrm{Na}$ and $^{32}\mathrm{Na}$ imply that these nuclei are more tightly bound than expected from theoretical predictions.NUCLEAR STRUCTURE $^{11}\mathrm{Li}$, $^{26\ensuremath{-}32}\mathrm{Na}$; measured atomic masses. On-line mass spectrometer.RADIOACTIVITY $^{11}\mathrm{Li}$; deduced $log\mathrm{ft}$.

Hali tarjima qilinmagan