Subject: Re: HyperNMR

From: Joel Polowin <[email-masked]>
Date: Mon, 25 Aug 1997 09:12:17 -0400

Adnan Hazar <[email-masked]> wrote:

> "There are too many NMR atoms [37]. You may not be able
> to complete the spectral calculation."

> As I have been communicating with the software company the problem is 
> that there are too many NMR atoms for the PC configuration I have.
> Although,
> I recently upgraded the memory to 64Mb, still not enough simply bec \
> there
> are 2^37 (1.37xE+11) spin states which require a lot of memory.

> I'd appreciate any comments which would help me to tackle this problem
> either at the software or hardware level.

Hardware level: nothing you can do; that kind of memory simply
can't be packed into a PC.

Software level: You may be able to reduce the number of spin
states by marking some protons as rotationally equivalent, such
as the three protons on a methyl group.  (Use with caution: for
example, the six protons on two different methyl groups are not
necessarily all equivalent to each other!)  Apart from that, your
best bet is probably to calculate the spectrum for only part of
the system at a time and then take the total spectrum as being the
sum of the spectra of the parts.

Joel Polowin
[email-masked]