Re: Masking

[vonrhein@GlobalPhasing.com (Clemens Vonrhein)]

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>
>  dm will generate itts own mask if you ask it to. You must give the
> sovent content and ask for NCSMASK NMER 2 ( see "advanced keywords"
>
> Eleanor

I found that this options works very well if your initial NCS operators
are quite accurate and the starting phases are reasonably good. 

In cases of poor NCS operators and/or very poor phases I usually use a
simple multimer mask (e.g. a huge sphere or slice around centre of NCS
symmetry if it obeys pointgroup symmetry). This allows refinement of
the NCS operators up to 5 degree (rotation) and/or ~ 5 Angstroem
(translation) away from their initial values. A correlation based
initial mask will tend to 'stick' with the initial NCS operators - on
which this correlation was based! (see e.g. GETAX documentation).

Clemens
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