Phương pháp biến đổi Laplace, phép gần đúng điểm yên ngựa độ chính xác cao ứng dụng cho việc tính mật độ trạng thái dao động của các phân tử trong động học của phản ứng đơn phân tử. Phần 1.

Abstract

In the paper the calculation of density of molecular vibration states has been performed by Laplace transformation approach, i.e reduced to the evaluation of  inverse Laplace transform of  partition function by the aid of saddle point approximation method: The exponential of  intergrand in inverse Laplace integral is presented in Taylor series, in which at the saddle point the first derivative vanishes, then, the density of vibration states  the inverse Laplace transform is integrated through the steepest descent which is in imaginary direction having the saddle point as abscissa on the real axis. Finally, this process of treatment give the expression of density of  vibration states containing terms of  from first up to fifth orders of accuracy, which have been easily calculated on computer.