[molpro-user] pec calculation

[Wang Mingwei]

Hello everyone,
I am doing the pec calculation of one small molecule. My question is that the 
calculation stopped when the bonding length is equal to some numerical value. 
For example, when r=2.137A or 2.187A or 2.337 or 2.387, the calculation 
finished normally; but when r=2.237 or 2.287 or 2.487 or 2.587, there would 
be error in the calculation and it would stop. The error information is same:

Catastrophic failure in diagonalization(hsdel)
 The expansion set has become singular
 This difficulty can arise for many reasons
 Sometimes it helps to redefine P space
 Otherwise, try increasing or decreasing reference space or nstati

 ERROR EXIT
 CURRENT STACK:      CIPRO  MAIN

Thanks for your suggestion.
mingwei

Mingwei Wang
College of Chemistry and Molecular Engineering
Peking University

mingwei at hpsv.pku.edu.cn