Mass Parabola

# Mass Parabola X M(A,Z) = ZMH+ (A-Z) Mr- - B(A,Z) C2 GAtomic maps M(A,Z)C2 = ZMHC2+ (A-Z) MnC2 GVA +asA + 2/3 2 1232 ACAV + aasy (A-22)2 - S A

The value of S is - (1) 35. for even Z- even N A=even 0 for eronz -odd N or add-Z.evonN A=odd - apA -3/4 for add Z- odd N. A-evon Two value of mass for even-A For A= even upper parabola (odd Z- odd.N) S=-apA-3/4 Mass II) M lower parabola (evonz- - even N) Z S= + ap 3-3/4 0> M= ap 3 1/4 M(A,Z) C2 = ZMHC2+ (A-Z) MnC2_ avA + as A 2/3 z2 + ac A 1/3 + Gasym (A-22)2 - S This Can be A 1 written as- 2 M(A,Z) c2= f(A) + qz + rz2 where , f(A)= A(Mnc2 avt aasym) + as A 2/s - s 2 = - 4 aasym. - (Mnc2- MHC2) r = A (9cA243 + 4asym)

eqn (2) is the equation of a . parabola for a given A(isobars) For most stable iso bqr 2M/A,2) = . O az A bout Odd A=135 only one parabola $ one value of mass (8=0) M(A,Z) lio. by (c) stable 3+ Te : Xe Cs S3 € Geture ge 52 $55455 SS 57 SS N For A= 135 most stable isobar has Z = 56 All B", B+, electron Capture ends at this point

Even A= 102 odd oddN is if Even Z - even N M(A,Z) (s= +apA'le) B+ B unstable 5 BT Two stable Mo Tc Ru Rn ed FJ (d nuclei. 42 43 44 45 46 47 48 Z Two stable even - even isobar (A-even) In few Cases, three stable even - evon psbar (isobaric-triad) at a given mass no. are known.