画红勾的题,谢谢大家
3个回答
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15、
(1)(-d^2/dx^2+x^2)e^(-x^2/2)
=-d[e^(-x^2/2)*(-x)]/dx+x^2*e^(-x^2/2)
=e^(-x^2/2)+e^(-x^2/2)*(-x^2)+x^2*e^(-x^2/2)
=e^(-x^2/2)
所以e^(-x^2/2)是算符(-d^2/dx^2+x^2)的本征函数,本征值为1
(2)(-d^2/dx^2+x^2)[xe^(-x^2/2)]
=-d[e^(-x^2/2)+xe^(-x^2/2)*(-x)]/dx+x^3*e^(-x^2/2)
=d[e^(-x^2/2)*(x^2-1)]/dx+x^3*e^(-x^2/2)
=e^(-x^2/2)*2x+e^(-x^2/2)*(x-x^3)+x^3*e^(-x^2/2)
=3x*e^(-x^2/2)
所以xe^(-x^2/2)是算符(-d^2/dx^2+x^2)的本征函数,本征值为3
后面的题都用一维势阱的薛定谔方程求解即可
(1)(-d^2/dx^2+x^2)e^(-x^2/2)
=-d[e^(-x^2/2)*(-x)]/dx+x^2*e^(-x^2/2)
=e^(-x^2/2)+e^(-x^2/2)*(-x^2)+x^2*e^(-x^2/2)
=e^(-x^2/2)
所以e^(-x^2/2)是算符(-d^2/dx^2+x^2)的本征函数,本征值为1
(2)(-d^2/dx^2+x^2)[xe^(-x^2/2)]
=-d[e^(-x^2/2)+xe^(-x^2/2)*(-x)]/dx+x^3*e^(-x^2/2)
=d[e^(-x^2/2)*(x^2-1)]/dx+x^3*e^(-x^2/2)
=e^(-x^2/2)*2x+e^(-x^2/2)*(x-x^3)+x^3*e^(-x^2/2)
=3x*e^(-x^2/2)
所以xe^(-x^2/2)是算符(-d^2/dx^2+x^2)的本征函数,本征值为3
后面的题都用一维势阱的薛定谔方程求解即可
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