# Single scalable brackets (bra-ket)

Dear all,

I am a bit lost on how to split the bra ket operator `langle <?> mline <?> rangle` . I am aware of the manual which says:

For scaled brackets use none as the bracket name

a = left ( a over b right none newline left none phantom {a over b} + c right )

[…]

Be sure to put spaces (gaps) between elements when entering them directly in the Commands window. This ensures that the correct
structure is recognized.

therefore to represent this

I used the followings

``````iℏ d over {dt} none mline ψ(r ,t) rangle  = H none mline ψ( r ,t) rangle
``````

and

``````iℏ d over {dt} phantom mline ψ(r ,t) rangle  = H phantom mline ψ( r ,t) rangle
``````

but the results are both wrong because these are not brackets in the sense intended from the manual. How can I proceed?

Thank you for your time!

(See also How to use Dirac bra-ket notation)

Use `iℏ d over {dt} left lline ψ(r ,t) right rangle = H left lline ψ( r ,t) right rangle `

`left xxx` and `right yyy` must occur in pairs.

EDIT 1 The appearance of the brackets can be slightly improved with:

`iℏ d over {dt} \ lline ψ(r ,t) \ rangle = H \ lline ψ( r ,t) \ rangle`

i.e. you replace `left` and `right` with `\`.

This turns the brackets into non-scalable ones. This may be an inconvenience in some contexts.

To show the community your question has been answered, click the ✓ next to the correct answer, and “upvote” by clicking on the ^ arrow of any helpful answers. These are the mechanisms for communicating the quality of the Q&A on this site. Thanks!

In case you need clarification, edit your question (not an answer which is reserved for solutions) or comment the relevant answer.

It works, thank you! Same remark as the other solution: the quality of the brackets is different (worse) compare to `langle <?> mline <?> rangle`

Don’t know how it works, but `\` seem better than my proposal.

It is an escape mechanism. The bracket/parenthesis code after it is no longer considered a must-be-paired bracket but an ordinary character. Since it is no longer scaled vertically, the angle is better looking. But you must also escape the other parenthesis otherwise it is orphaned and you get an error.

It seem to be that `left none` is the key.

Give a try to

``````iℏ d over {dt} left none mline ψ(r ,t) right rangle  = H left none mline ψ( r ,t) right rangle
``````

Tested with LibreOffice 6.4.7.2 (x86); OS: Windows 6.1.

Add Answer is reserved for solutions. If you think the answer is not satisfactory, add a comment below, or click edit (below your question) to add more information. Thanks.

Check the mark () to the left of the answer that solves your question.

Yes, it works in the 7.1 version too! The only remark is that the angular bracket looks different (i.e. vertically stretched and therefore “less angular”).