#settings Nmr keys

Eight #settings keys give a program its own NMR Analysis setup: which sample it runs on, the field, the RF amplitude, relaxation, the pulse envelope, the readout mode and the receiver channel. They live in the file header like every other setting.

Reference

Key	Default	Type	What it does
`NmrSample`	`"chloroform"`	sample key	Spin system for the NMR Analysis tab. Keys are listed on the NMR sample library page.
`NmrField`	`11.74`	tesla	Static field B0 for the NMR Analysis tab (500 MHz for protons).
`NmrRf`	`0.587`	millitesla	RF field amplitude B1; sets pulse lengths (0.587 mT is a 10 µs proton 90° pulse).
`NmrT1`	`2`	seconds	Longitudinal relaxation time used for acquisition lengths on the NMR tab.
`NmrT2`	`1`	seconds	Transverse relaxation time; sets the line width 1/(πT2) on the NMR tab.
`NmrPulseShape`	`"square"`	square \| gaussian \| sinc \| hermite	Envelope drawn and timed for RF pulses on the NMR tab.
`NmrReadout`	`"pulse"`	pulse \| none	"pulse" applies a 90° readout pulse before acquisition; "none" acquires the state as it is.
`NmrChannel`	`(first isotope)`	isotope	Which isotope the receiver listens to, for example 1H or 13C.

Example header

#settings NmrSample "crotonic_acid"
#settings NmrField 9.4
#settings NmrRf 0.3
#settings NmrT1 5
#settings NmrT2 0.9
#settings NmrPulseShape "gaussian"
#settings NmrReadout "none"
#settings NmrChannel "13C"

Sample keys are listed on the sample library page. Values without spaces may be written with or without quotes; numbers are plain.

How they are applied

The keys are read whenever the code changes and forwarded to the NMR tab, so a file opened from Storage brings its spectrometer with it.
Only the keys present in the file override the toolbar; the others keep whatever the toolbar shows.
A sample that has fewer spins than the circuit uses is not applied; the tab picks the smallest sample that fits, as it does when you choose one by hand.
The tab's toolbar can still change everything afterwards; the file is a starting point, not a lock.